If you invalidate gender inequality by pointing to women calling other women "bitches", you don't know the first thing about human behavior.
There are a few go-to responses when talking about gender inequality. Some include outright denial of any gender inequality (even though women still making 75 cents to every man's dollar). Other include extreme takes on what equality means ("If women are the same as men, that means I can punch women in the face, right?"). But one of the most popular responses is, "Well, look at how women treat women! Obviously women are to blame for this problem."
People who turn to this woman-against-woman behavior are people who either have no clue how human behavior works (or is willfully ignorant of it). Woman calling other woman bitches, enforcing impossibly beauty standards, even undercutting each other at work in front of their male counterparts, is just one tiny example of the oppressed turning in on itself.
You see it everywhere, from places of extreme poverty to reservations -- somewhere along the line, some of the prisoners start doing the job of the guards. Somewhere along the line, things that were started by the captors are perpetrated by the captives.
And why? Because, at the end of the day, our brains are wired for survival. It can be as overt as fighting for food and it can be as subtle as turning on the weak link in a meeting. There is something downright instinctual about inevitably throwing whoever it is that we need to throw under the bus. So suddenly, we get women calling other women sluts and whores. We get women who are the first to point out all the reasons why a woman "deserved" her assault. We get women who are quick to reinforce what it means to be attractive in our society. We get women who will be the first to step up and talk about how they are not like "other girls" (which I've ranted about already).
And the killer is that no one wakes up and decides, "To save my skin, I am going to cheerlead the confines that society has put on me!" It's much subtler than that. It's always much subtler than that.
Which is why I make such a fuss about all the subtle shit. Calling women "girls" and saying, "we're not like other girls." Because we don't see the reasons when we go broad. We can't see trees because the forest should be made of something else entirely. We don't recognize that we are products of our environment and the tiniest little things enter our schema and shape an entire way of doing things.
It's just exhausting to hear people brush off inequality, citing this as their very reason, not getting that all they're doing is reinforcing the locks on the penitentiary, all the while denying there are guards in the first place.