It's also that women in groups tend to apply far far more social pressure to enforce conformity within the group. Far more than within male groups. And the consequences for a woman becoming ostracized from the group are likely a bit more severe (I don't think I need to expound on a lot of what that usually entails).

Plus leaving a group and trying to join another is probably tricky too. Not only is she likely to be followed and harassed by members of the original group, female groups in general seem to be rather gated and closely guarded against new women in general.

Pretty much the only surefire alternative to that fucked up dynamic is to find a decent husband, who has decent friends with their own non-harpy wives. Etc etc. Women really are their own worst nightmare. And feminism only adds to the poison and toxicity.