Hmmm.
I don't think there's anything wrong with the term per se , it's just a description. sometimes having a night out with only women is awesome.
I am hoping to arrange a night out with a few female friends whom I share a common cultural interest with and I respect as people and I hope to enjoy their conversation (which will probably involve the common cultural interest). I wouldn't want any male friends attending.
My individual experience though is the phrase has been hijacked.
when individuals use this, there is a big difference between rhetoric and reality (a bit like the kind of night out in the Office which David Brent organises).
Whenever I've had a potential "woop woop Girls Time" presented to me it inevitably is really, really shit and despite promises of female solidarity it always is a bit flat.
It's the kind of thing a netm**ms user would say you know what I mean hunny babe?