This is the key element of incel culture - if one member of the group tries to improve themselves in anyway, it's an attack on the whole group and they are ostracized from what feels like their only social group.

"What? You started exercising and showering? Who do you think you are? Who are you trying to kid? You're just playing the slut's game, man"

All social bubbles are at least a little harmful - but incel culture is more than that, it's purposefully self-destructive. You have to be sad, miserable, and let your life fall apart to belong. It takes advantage of social instincts in the worst possible way.