I just think these particular guys are a bunch of men who have never so much as dipped their toes into fanfiction-fandom, and had no clue that it would consist mostly of women, or how to talk to that demographic without sounding patronizing.

Yeah. You may very well be right about that. And it's problematic, because they clearly want to exploit fanfiction writers (by making money off their work while giving them nothing in return), and since they're men and fanfic writers are (mostly) women.... I guess I can see how that situation might take on sexist overtones. And the way they've been talking to fandom at large hasn't helped any.

Whatever the reasons behind the way they've acted, I don't want anything to do with them, and I'm not surprised that there are lots of other people out there who feel the same way.