Many autistic people have the tendency to want to categorize things into rigid boxes. Men do abc, and women do xyz. Autistic women (a huge demographic on Tumblr) in particular tend to be gender non-conforming, often because adhering to the female gender role involves a lot of difficult social shit and uncomfortable clothes and makeup. I think autistic girls on Tumblr were trying to convey the feeling they had that they don’t quite fit into the “woman” box because they’re autistic.
All this gender stuff is nonsense, obviously you’re a woman whether you adhere to your gender role or not, but that’s not what gender ideology peddles.
ETA: I know that’s a random.txt, but it came from a Tumblr “list of genders” that went around the site back in the day. My husband actually had a sociology professor print that post out and hand it out when he was in college.