Huh. I suppose I could speculate that it's something to do with the factors that pull people into GD (which are very weak right now, but still), which (to my knowledge) are a) Dwarf Fortress, and b) word-of-mouth. People either come for Dwarf Fortress, stumbling into General Discussion (like I did in 2019), or a friend who's already on Bay12 pulled them in. My own data suggests that both occur roughly equally, but I only have 2 years of data to work with (also, I've been here for 2 years? Wow.). I suspect the Steam release of DF will bias the results towards DF, whenever that happens.
Are AMAB people (regardless of the gender they currently are) more likely to be pulled in by violent games (and DF is definitely violent if you go by how it's described outside of Bay12)? That's the thing my speculation is hanging on. Even if they push hard to not be male, completely going "fuck being a man, I wanna be (a) ____!", does the cultural baggage still affect them enough that it still affects the choice of video games that they choose to play and subsequently join the community of? Or maybe I'm forgetting order of operations; they join Bay12 first, then they realize they're trans. It's slightly more plausible that way around.
I mean, it's probably total bullshit to think of it this way. My Bullshit Meter's in the 20% - 40% range, likely an underestimate because it's my own "work". There's an off smell, but I can't pinpoint where.