I mean I agree that people who are involuntarily celibate are super toxic and often create a women-hating personality where this would be true 90%+ of the time... but I don't see how it is intrinsically part of the definition. More of a statistical probability.
Nobody's involuntarily celibate. If you're single, it's because you're not interested in dating any of the people who are interested in dating you.
Casual sex with an Instagram model might be unattainable; but getting lucky after half a dozen dates with a lonely widow, that's doable no matter who you are.