[socalgal2]

It's a stereotype that women are directly mean to other women more than men are mean to other men. No idea if there is any data to back that up, only that it's a commonly repeated meme.

https://www.google.com/search?q=women+are+just+horribly+crue...

There's also culture at play. I don't know if men affectionately dissing their friends is universal but there's plenty of related things like:

In Japanese culture you don't brag about co-workers or family to outsiders. Outsiders you treat with respect. Insiders you don't. The fact that you don't get the more polite treatment is proof that you're an insider. It's a common scene in stories where someone asks to stop being treated like an outsider by specifically asking for the less polite language. You can also watch the ribbing man to man, man to woman, woman to man, woman to woman. I don't know if there is data on which is more common.

[daseiner1]

the stereotype is also that when men don't like each other they'll just get into a fight once and move on whereas when women don't like each other they'll tear each other down in extended social and psychological campaigns

[BurningFrog]

I suspect this is partly true:

Once they've had that fight, they both know who won, and their pecking order is established. Then life can go on with that settled.

[daseiner1]

yes, but of course the "pecking order" is more complicated than that. oftentimes the victor (the "alpha") gains respect for his (defeated) opponent for having the balls to challenge him and is thereby far more liable to include him in matters of importance

fighters tend to respect fighters if they fight a clean fight