Good point, but I still think incel carries a certain connotation of misogyny with it, though. Otherwise you would just say “virgin”

Maybe if they’re really young and weren’t on the internet when the word became popular, sure

Not really. Incel implies a level of indoctrination into a misogynistic POV that has you convinced that you’re better off alone. It’s not the same as insulting someone for simply not having had sex yet.

edit: not that I think either is a productive thing to call another person