From what it seems, these communities believe that being very vocal with their "I love baby diapers but I would never, ever, ever, EVER be aroused by an actual baby's diaper!" rhetoric is good enough. It's wildly unconvincing outside of radical queer ideologues and libtard progressives, and even they don't always take too kindly to the attempts to worm their way into general acceptance.
Oh, yeah, I completely agree.
If you're someone with a kink/fetish, just keep it to yourself. There isn't a single kink/fetish that doesn't get some measure of scorn from somebody and the only reasons psychologically to signal its your fetish is because it arouses you in some capacity (be it the alerting itself or the people reacting to it), or you're hoping to find more likeminded people such as yourself to gush over it with like a fan signalling their love for X-franchise. I don't care if you're into a particular kink/fetish or whathaveyou, but is it absolutely
necessary to tell everyone you can about it? This forum is filled with people who would be spared mockery and derision if they weren't so enamoured with themselves that they could resist plastering their private lives all over the place. Statistically speaking there might be some absolute degenerates on this website who are in good standing with other users simply because they don't have to plaster their list of fetishes everywhere.
There's people who simply
can't separate themselves from their fetish, because that's how important it's become to them. We see its consequences with transgenders, but it can apply to
anything.
Some of the entries on OP's list don't even make sense to classify as a fetish to me. >50% of people have a "clothing fetish"? Specific body part fetish, but that includes things like boobs? Are you for real? First of all if its over 50% you can kinda lump it in with normal human sexuality, if more people feel it than not. Second of all, a lot of them fall under "things that accent or tempt you to imagine the actual sexual characteristic" which to me seems like the clothes aren't even the point of the alleged clothes fetish. Like really? Liking skimpy clothing is a specific fetish when all it is is clothing that reveals more of the body? I've seen a clothes fetish in some fucking lolcows and it's not that, it's retards obsessively wearing/talking about women wearing overalls because they played too much Mario in their autistc youth. I get what OP is going for with this but a chunk of it reads like psychobabble "normalization" used by creeps, you commonly see them categorizing things ever closer to their pet obsession as "a type of [blank]" that contains said obsession. And I'm not saying OP is one of those creeps, just that the retarded literature is easy to use to confirm ones own beliefs. While I can agree that fetishes are more common than most are willing to accept, I reject that framing that some of these more normal things are "erm acktually a fetish" and it seems more like an attempt by fetishists to try to ease normies into not thinking they're weird.
Anything!

They aren't measured by intensity or focus, just whether X-non-sexual object/thing provokes intense fascination, attraction, or arousal. By definition anything can become somebody's object of paraphilia. Short hair, eyes, button-up shirts, obscenely long walls of text—
anything.
Though "clothing" is so broad, vague, and nebulous it could be anything from bikinis and lingerie to ballroom dresses. If you find X-thing "hot" that isn't inherently sexual by itself, it still counts.
I understand your perspective though. With no narrow definition, there's too much dumb shit to come from it. One example: women are a fetish in of themselves to men in some (insane) circles.
Paraphilia = sexual attraction for
non-sexual objects
If you're of the view that men objectify women, and women aren't intrinsically sexual by nature (or your definition of sexual is ungendered), this can lead to the conclusion that:
1) A man's love for a woman
cannot be sincere, because he views her as an object (i.e. men are not capable of true love)
2) A man's love for a woman can only be seen as sincere if the woman is not sexually attractive thus not provoking arousal (i.e. a man's love is only sincere if the woman is fat or ugly)
3) "Male gaze" (i.e. men are inherently lust/sex driven, anything that can serve as male paraphilia is best avoided at all costs)
Technically, any use of the word "fetish" not describing part of the body is being used incorrectly, but the word is synonymous with kinks, paraphilia, and so on. I'm using them all interchangeably to so it's whatever
Him listing ABDP as "normal" could be him knowing on some level that it's abnormal, but doesn't want it to be, because otherwise it makes him by extension abnormal and the fetish itself degenerate/wrong.
This is the sort of thinking reinforced from sequestering in echo chambers or by absorbing 0 contradictory viewpoints. Since he might not willingly enter forums/chatrooms/etc with people who share this kink he's only had himself to reinforce it. People can become their own echo chamber, essentially. If you have an idea, become fixated on it, and hear no contradicting viewpoints, it grows to become a larger part of your life—too large, for some people.
The fix is to:
1) Not be dependent on public consensus to shape your moral core/feelings/opinions/habits, etc
2) Not be too dependent on your view solely to entrench bad habits/ideas/beliefs, etc
3) Humility (Being able to accept that you
could be wrong is a very important and often neglected concept)
Balance is the key. And don't get emotionally invested in shit that doesn't matter (which is easier said than done, but still—at least
try to).
He may place some value in the opinions and users of Kiwifarms, so he wants his fetish to be affirmed or tolerated in some way as a form of moral consent to continue indulging. This is common across the political spectrum and with both sexes. In more exclusionary communities, some people experience personal gratification at being "one of the good ones" from a group that is otherwise scrutinised, and he possibly sought that from kiwifarms of all places. Requiring consensus or needing to know the feelings of others is also a vaguely "feminine" way of thinking. I use "feminine" in lieu of a better term, but we all understand it to be soft and pliable.
If he's a homosexual, a form of "self-correction" typically seen in more conservative-minded individuals is to adopt more feminine mannerisms (hence the need to seek some kind of validation). This sometimes has escalated into full-blown transvestitism (i.e. become the "woman" they ought to be, being attracted to men) but could also translate into the adoption of more womanly mannerisms and characteristics, such as excessive empathy, or changes to clothing, manner of speech, etc.
Continuing to be the armchair psychologist I am, maybe he's just attracted to older women, and the last time he received unconditional love from such a woman was when he was wearing nappies, and so associates the two?
It's possible his diaper fetish comes from him feeling shame over his homosexuality, and is "self correcting" with some latent desire to be more womanly, and this has clashed with his sexual urges for men. In other words: he wants to play the role of "mother" to a grown man. It doesn't necessarily have to be sexual, or come with the tranny baggage, but it's possible.

This has translated to the fetish being "normal" in his mind, because he sees it as being rooted in motherly parenthood. The "common in females" remark could be the buried lede. Him also highlighting people who do it as a form of trauma-response could point to his desire to coddle those he sees as vulnerable? He knows
his reasons for liking it, but to put them out there wouldn't just prompt pedo accusations, but also tranny ones as well, assuming I'm on target.
Or his aforementioned homosexuality effeminising some of his behaviours translates to him showcasing a self-detrimental level of empathy for people he doesn't even know. I do think him not mentioning the elephant in the room with regard to diapers—shit, soiling, and babies—is more from him perceiving it as tame a light as possible because he doesn't see the fetish as being dominated by "gross" people.
If this is the ballpark, then the fix to certain fetishes/paraphilias is to atomise them into their core parts, internalise the parts which are least harmful as what
actually titillates, then dismiss the rest. In this context, the corrupted core of ABDL is the desire to care for someone in need of caring/to be needed/to be loved unconditionally/to be coddled and so on. In lieu of experiencing the real thing, the best they can get or experience via proxy is play-acting as a helpless baby with someone playing the role of a needed parent i.e. an imitation relationship of two-way unconditional love. And the act of "wearing a diaper" by itself is because it's associated mentally with being weak, useless, and vulnerable, yet ultimately carefree, and being able to choose when and when not to experience that feeling whenever he wants gives him some measure of control in his life—something he feels he's missing otherwise
.
All kinks/paraphilia could, on some level, be a corruption of good, though you'd need to break down them individually. In this instance, the corrupted core of ABDL could just be to care for someone in need of caring, or to experience some facsimile of parenting in lieu of actual parenting. A positive sentiment/want that has otherwise been corrupted because it's tethered to sexual gratification or some otherwise bizarre non-sexual behaviour.
TLDR: Some kinks/fetishes are possibly corruptions of positive feelings/wants/actions, which is why there's such strong emotional attachment with some people.
Being made aware of this, and untying them from sex, could separate the good from the bad.
If FemboyFartHuffer has a diaper fetish, it's wholly possible he longs for what is associated with the imagery on an emotional level. Whilst his exclusion of the grosser elements could be a means of validating, that could be his earnest overview of what it is to him.
The "fix" then is to split the positive emotional associations from the negative physical acts and apparel. i.e. he wants to feel in control of his life, to be carefree/stress-free, he wants to be "safe" regardless of his own agency, he wants to care and/or be cared for, and otherwise he just wants to be doted on/loved.
Accepting that he wants these more normal wants and desires would mean getting some faux version of them via the fetish is unnecessary.