because they don't skateboard

Because they already use this term for themselves and their weird misogynistic culture centered around their personalities being too repulsive to get them laid.

You can call them anything you want. If you want people to know what movement you’re referring to, you’re going to need to call them incels.

Because it's an accurate, specific descriptor for a distinct, vocal, militant part of today's antifeminist movement. Having a name for that is more valuable than tiptoing around fragile masculinity. Incels, MGTOWs, and PUA / Andrew Tate types may all operate under the same ideological framework where they just take varying places within their self-created hierarchy of masculinity, but are seperate scenes with seperate avenues of recruitment, and they harm women in different ways. They need to be understood accordingly, because they require different threat models and countermeasures for women to deal with them. When we're talking about counters to antifeminism and misogyny, it's not just a political struggle, it is part of our personal lives and our everyday safety protocols especially for heterosexual and bi women who are out there dating men. But even if we're lesbians, or bi women who've given up on dating men, or women in relationships with men who aren't problematic, there's still situations were we have to recognize and react to different kinds of radical misogynists, be it in the nightlife, in our hobbies, online or when our friends are affected. Anti-patriarchal action isn't an abstract, it's a fairly hands-on mode of urgently needed praxis when misogynists organize to share techniques for harassment and assault, methods of domestic abuse, strategies for divorce and custody cases or a modus operandi for spree shootings (and yes, all of these happen on a widespread basis).

Like i said before, i object to using the term incel outside of the incel movement, i'm not a fan of how the usage is widened because virgin shaming is reactionary and i do not endorse that. However, belittling the lonely and touch-starved is fortunately not how the term incel is commonly used on this site, we are aware of these nuances, just as our mods take a firm stance against related issues like body shaming or ableism in the callouts of reactionaries. All of that is against the site's TOS and all of that is actually enforced and understood by the community.