This kind of calls back to the wheelchair discussion. ("If you're in a wheelchair all the time in life, why not imagine being able to walk?")
If you're stuck as a human in your meatbag life all the time, why bother pretending to just be more of the same? Why not the chance to imagine being something you are not? Isn't that the point of the game? (not that I, being a robot, am capable of imagination)
Being able to walk/free of a mobility device is a common state of existence there's a good chance the player experienced this at some point.
If you are a gnome who got reversed-isekai'd and can prove it, we can talk about you being allowed to play a gnome in the game.
I would make a person in a wheelchair play someone in wheelchair if they were very clearly rolling dice one-handed jacking it to the thoughts of being able to walk and participated in weird communities where they made are where being free of wheelchair gave you shitting dick nipples.
If the expected game path involved lots of rolling up inclined planes, it's going to ruin the game experience for everyone else when they can just climb some stairs.
And as addressed, (except for gnomes/goblins/tabaxi) its a whole different story if I know and trust a player.
The other thing is "Human" covers a huge array of experiences. As
@Corn Flakes points out, unless you are wielding a broadsword and hacking up skeletons on the daily, you are already stepping outside of your ordinary.
You can be a merchant, you can be a beggar, you can be a veteran, you can be a criminal, you can be a spy, you can be a runway, you can be a researcher, you can he an honorable warrior, you can be a craven back-stabbing profiteering coward.
If you can't come up with a good human character to play, that's a lack of imagination and creativity that putting "Kinder" in the race field probably won't fix.
Doing weird
freakshit races is usually because either A) they want some racial trait to do a broken build or B) they want to use one aspect of that race's personality, ignoring the rest, to be a disruptive annoying table twat. And probably both.
That's the reason I often roll nonhuman characters myself, both in tabletop and vidya. It's a fun storytelling challenge to stop and ask myself "okay, so how would a tiefling react in this situation? How will they interact with the world around them? Do I try to play nice, or do I just assume that everyone else is gonna be an asshole to me because I'm a tiefling and respond accordingly? Or do I just not bother trying to interact with people and let the party do the talking while I lurk in the background and look menacing?"
If you do it right, it really adds a lot of flavor to the experience. If you do it wrong, you're That Guy and everyone's gonna hate you. It's a fine line to walk and it's not surprising that people often wind up on the wrong side.
You are in the extreme minority.
Most players who do actually role play their non-human/non-core are only looking to indulge some fetish or fishing to break the game.
Hell, usually the most I'll get out of a dwarf is they want ale at the tavern or maybe do some stonework inspection (but that's usually because they have a mechanical advantage) and some racism at Elves.