I cannot speak for other people, but for me personally, the pseudoscientific reactionary ideas you mention were very appealing to me at one point in time because I had, and still have, a very difficult time attracting women. There was a period of time in my life when I spent a lot of time reading pickup artist/RedPill/men's rights content on the Internet until I managed to escape it, mostly via the help of supportive friends. I think that there are a lot of misguided nerdy young men who fall into this frightening rabbit hole, where one bad ideology leads to another.