christ, it's not a derogatory term. words mean whatever you want em ta mean, so if you take it as a personal insult, that's only because you want it to be one. now as for why you'd do that, well, the human psyche's a twisted landscape. relax, people. when yer 70 years old, you'd likely kill a man with a hammer just to be referred to as 'girl'. life's too fuckin short to be offended by stupid shit.