Off topic but I can understand why girls don't like being referred to, directly or indirectly, as a "bitch". As a guy its the only thing that makes sense to call girls sometimes. examples.
When they're whining at you.
Why didn't you call me when you got home from skiiiiiiiiiiiiii-ing (notice long drawn out whiney skiiiiii)
Why you bitchin at me like that?
When you're referring to one.
Dude I was at this party dancing with some bitch and she was grinding me like it was her job then I go to hook up with her there on the dance floor and guess what that bitch says? Oh I have a boyfriend at CSU.
or
This bitch was giving me head and I asked if she wanted to get into bed and fool around and she said I'm not really like that. Bitch my dick's in your mouth.
So again I will never refer to a girl like that in front of them, but on a adolescent male dominated website I'm sure you see it more than your peers. To be honest I'm surprised girls don't have a derogatory term for guys you girls use when talking to your friends.
example
I was flirting with this dick all night basically throwing myself at him and he tells me he's going to get a beer and he'll be right back. Then after ten minutes I walk around a bit and BAM i see that dick making out with some blonde Frat Rat girl.
or
My cock sucker of a boyfriend and I planned a romantic movie night together after he got back from skiiiiiiiii-ing with his friends and he came over so stoned that that cocksucker fell asleep half way through The notebook. He didn't even go down on me later!
Girls need a term for guys then they'd understand why we use bitch so frequently.