I remain convinced that pooning is what happens when autism, a feeling of confusion and lack of safety, and porn/grooming meet.
Thinking back on it and what stands out first with pooners. I think it's not the size, it's not that they are lesbians.
It's that they reek of insecurity. The play pretend is over the top, and they get uncomfortable when in presence of actual males because they realize how out of place it is. When you are something, you don't need to oversell it, you don't think about it. They suddenly don't know how to act anymore, feel judged (maybe with reasons).
I think earlier in the thread, there is an example of Ellen complaining about how weird and uncomfortable it was for her to be with a cast of all cis males. This just goes to show how much of man she really is when the company of peers makes her uncomfortable.
On the other hand, lesbians who have a dominant (sometimes masculin) personality are much more assertive and confortable with themselves. They scare me a lot more than a girl dressed up to look like a guy. They're not confused about where they sit and it makes a world of a difference.
I only ever encountered two pooners in the wild with which I had interaction (both of them barmaids) so I might be biased. One of them was actually kind of shocked when addressed as a woman. We just thought she was really into hip hop with her baggy clothes, it had not even crossed our mind she was supposed to be a man. Must have hurt.
My harmchair psycho analysis on this is that they're just very insecure and confused indeed. I do believe the theory that a large part may have been abused in the past and are trying to gain back some form of control. But that just reinforces how much they are just broken individuals trying to live a life they were never meant to. Even if they wanted to, they could never be that confident in her skin lesbian who just hangs with the guys and don't overthink everything. It's just cope.
Autism, I don't know.