Why is it that every dude who troons out suddenly cares so much about trans youth and protecting them? I mean, outside of grooming children. Is it some gross, over simplified way to prove how motherly they are?
Others have chimed in with some good answers but I'm going to back this up to an out of groomer context.
Say you've wanted to paint your whole life, but you couldn't do so until you were an adult and had the time/money/encouragement needed to do so. Once you start painting, you feel extremely happy and fulfilled, and wished young you could experience the same joy. It may be too late for young you, but there's many kids and teens out there who could enjoy painting but can't due to the same restrictions as you. Ergo, you donate to charities or schools that promote art programs or start helping underprivileged kids yourself. It's nice to share your passion with others, have every person get their day in the sun, pass something down to the younger generation, and such. It helps you come to terms with your past self as well.
Protecting trans youth as an adult is the troon equivalent of that. Sometimes it is because the person thinks puberty blockers
licherully make you indistinguishable from the natal version of the sex you're trying to become, thus fulfilling latent protection from all the bullying said trans person got in highschool (likley not for being trans, but they think IF I HAD BEEN THE OTHER SEX MY CHILDHOOD WOULD HAVE BEEN NEAR PERFECT BECAUSE THE SEX I'M TURNING INTO DOES NOTHING WRONG) and as a trans adult (trans people and even troon usually have enough empathy to not want others to be misgendered to death). Sometimes it is to live the fantasy of being a youngster out again. And sometimes, it's because all your other trans friends say it and half your friends are children anyway since you're into an autistic fandom of all ages like Pokemon and bond with children more because of your inept social skills.
For Aaron? I think he genuinely loves arguing with others and always feeling righteously against people he hates, which happen to be TERFs and Transphobes in this situation. He's the type of person who seems like he gets the BIGGEST ego boost out of "Hmm you're wrong and the law agrees with me, I don't make the rules, die

" rhetoric. I mean, look at his reddit tattoo. In another life he'd be some awful advisor in a court to a king, not quite royalty but fully willing to abuse it as often as possible to get his way. He's invested in trans kids because it is the current battle grounds of the Troon wars where he can strut proudly as a troon warrior (like philosophytube). I'm sure he is also living vicariously through trans kids too.
Trans is also his lifestyle. Any little thing that threatens it is the biggest catastophic event to possibly stopping it. It's not like a BDSM enjoyer who is sad that the club they like to go to every so often shut down, it's like someone who lives the adult baby enjoyer who's life REVOLVES around being an adult baby panicking at a town protest sort of deal. It's baked into his routine: wake up, get dressed, talk to your troon squad and assert how cool trans people are online, eat, show off your woman outfit of the day, go to work, check news for everything on troonism, post more about how troons rule, get off work and tweet more about trans stuff, maybe go to a LGBT club or hang out on discord streams and ignore your child. He's invested SO much time into "Erin the Troon who is a GREAT lgbT and Troon activist" persona that anything threatening to take down his happy persona he'll fight tooth and nail to keep it, even if it's a small thing like being made fun of.
Well, you can tell how high he rates - 2 am EST slot.
He can preach his troof to the drunks staggering home from closing time, and insomniacs who want nightmare fuel.
It could also be a schedule thing: he does have a son he has to take care of, and he's responsible enough to take the kid to soccer. It could be to fit him in when his son is asleep or something. Whatever it is, it's still funny and nice to see him on the ass end of the event. And he better not wake up his kid.
Another possible factor in addition to sexuality for Tony enjoying cracking eggs is because it is another power trip. There's nothing like being the one to convince someone else to make a big life changing decision and indoctrinatinf them into your cult. Not only will they adore you for being the catalyst for change, they will feel like they owe YOU, and thus can convince them of things more easily and have extra power over them.
I think general Christian proselytizing enjoyment could also be a part. He is part of a church after all, I'm guessing he's used to the joy of spreading the word.
“highly gay” oh fuck off and take those nasty moobs with you
Replace any variation of the phrase "highly gay" with "girl crazy", "female obsessed", or other more accurate terms and it becomes a lot more clear on what they mean.