Given this is a sociological phenomenon, it makes more sense to give them a more scientific designation even though some of their members may have called themselves in an ironic sense.
"Incel" is now widely used as a negative-connotation catch-all term for young loner men almost with the implication that they chose this life for themselves rather than being denied opportunities by society.
They didn't necessarily choose the life, but there's a lot of overlap between alt-right propaganda and the red-pill incel sphere. A lot of these young men are set up for failure, but then are propagandized to blame their failure on everything external, particularly women and minorities.
The truth is everyone can get laid, and it's not very hard at all. But the pre-requisite is liking the people who you want to sleep with, which is hard when you hate women.
While I understand the term fits as "derisive", I'm not understanding why you think it's a hypocritical term. It seems pretty clear that "involuntary" is correct, and a definition for celibate is "having or involving no sexual relations", so that seems to fit as well.