If you're just talking about the fediverse, it's probably because a lot of us (MtF's I mean) got interested in things like tech at a young age, and that interest just persisted into adulthood. Interests like that aren't pushed as much to people raised as girls, so a lot of FtM people don't really get into it, if they even have the chance to try it at all.

If you mean society as a whole, well there are a lot of reasons. A big one imo is media representation. Every single sitcom had a trans girl character at some point, but the only one I could think of that had a trans guy before the 2000s was the Golden Girls.

Depends on the circles you move in. On Tumblr FtM is (or was, when I used it) far more visible.

That's because the FtM lads are all too busy chopping lumber and winning bread.

Probably since it's a platform used mostly by dudes, who'll keep using it afterwards

It's because it is. The short version is because it's socially acceptable for a woman to be somewhat masculine but it's not socially acceptable for a man to be feminine. A man wearing makeup, a dress, etc. stands out way more than a woman wearing a suit, jeans, etc. It is believed that this results in higher rates of transwomen. Obviously this is an oversimplified explanation, but it's the gist of it.

Source: Multiple degrees in psychology.

I've always wondered that as well, it's really weird because you would think it's an even split but it ends up being so extremely disproportionate.

I can't figure out how to log off my computer