Thanks for elaborating. I mean, I would say someone who thinks they are autistic would most likely have a reason for that. Mostly that is more than one or or one very strong autistic trait. Without that I would ask how they concluded they might be autistic.
An then there is the somewhat tinfoil hat style idea that you have trolls and non autistic people in online communities to an extend who can make the majority if a group is very small and not moderated enough. That way you can end up with people preferring to judge if others are valid instead of blanket accepting everyone.
There are a lot of factors that can contribute to this. Also, I have met people who pretty sure are on the spectrum but who are ableists par excellence since they were molded to fit society’s standards. So, there is a ton of stuff to take care of in a sub like this.