I think a big part of this is very much a psychological issue.
Because squatting isn't 'common' for many people, it is experienced as more uncomfortable than it really is (even when it's done right - where there's no permanent tension from balance on your toes, for example).
Another example would be sitting cross-legged (or whatever that one leg over the other thing is called) as a man. I find that I and many guys I know naturally feel comfortable doing this, but we're taught from a young age that it's 'gay', so we learn not to do it.
I've noticed that people with autism spectrum disorder often have really odd ways of standing or sitting, and one particular thing I've noticed is that this often includes squatting, sitting cross-legged / yoga-style, or sitting on the couch with your legs folded up close to your body. In my case, these are things I often consciously avoid doing when other people are around, because it's perceived as odd or childish (or at least I think it is).
It would make sense that people with asd might just not care about or know these things, and do what's naturally comfortable/efficient.