When women in these situations make it clear that some behavior is not acceptable, they'll inevitably be met by "Woah don't be so serious, it's just a joke! Lighten up!" And the more upset and determined that woman is to make it clear that something isn't acceptable, the more likely they are to be labeled a bitch.
Because I'd bet you that 90% of the bad behavior you see in that type of situation isn't blatant sexism; it's small "jokes" and "jabs" that all add up to a bad workplace environment for women. And it makes it that much harder to defend yourself when there isn't just one glaring offense that people can blatantly see.
I think making this behavior unacceptable would be helped a lot more if men in the workplace stood up against it. It's not so easy for a woman to do it alone.