I'm half convinced they were made up by the left as the new "enemy" to justify the anti-male narrative. Had never heard of them until the subredit was banned, and then all of a sudden they make the news.
If legit incels actually started this movement themselves why would they they call it "involuntary celibates"? Insinuating that they don't want to be celibate, and if they don't want to be celibate, why would they be such woman haters?!
IMO the following is more probable, they noticed how the feminists are so hated and invented the male equivalent to be able to say, "seeeeee, women are oppressed and in danger, incels are proof of that!". Same for the alt-right or alleged nazis, a made up enemy to pin fake hate crimes on in order to prove that minorities are marginalized.
I'm not saying there aren't people who don't care for women or minorities but most of them just want to be left alone and don't go out of their way to cause any trouble for them.