Newgrounds, while low, has a deceny bar because old regulars from 2005-and earlier keep coming back to this site to bitch about how much greater it was back then and how nearly every joke this generation makes is an epic fail compared to their generation of "wins". As long as those hopeless regulars continue to return, there's an easy seperation between stupid users and extremely troubled users.
And I would think somebody who had autism or a condition like that would be warded away from this site to begin with: Seizures, flashes, disturbing images, depression. All the more reasons to stay away from the half-assed comments of the BBS.
Besides, I've only known two people here who actually show any ounce of humanity: Tom himself, because he's married and has a kid, and wwwyzerad who ended up joining the Navy or some station and actually posted a story about his feelings on it and his life thus far. Everybody else just rolls with the punches.
So yes, it'd probably be pretty obvious. That user wouldn't log in for a LONG WHILE if their autism was spiked by anything we said or that they heard from us.
Now YOUTUBE on the other hand, they're a bunch of savages. TO say an autistic person, more than ten or twelve would be lurking there, would not be that far off.