I don't think that's true. Something like a third of American women are anti-choice, typically because of their religious convictions. That is, their political beliefs are a function of their involvement with their community. Incels have a much more simple hatred of women and people in general, usually because of their isolation from any real community. Also there actually are female incels who, if anything, lean more radfem (in the sense that their first principle is hatred of men), and are generally pro-choice.