While I find it crass and unfair to call any promiscuous woman a "whore" (the male equivalent word seems to be the decidedly complimentary "stud") I've always wondered what's so bad about calling a prostitute a 'whore'. It saves on two syllables, and - let's be honest here - I'm pretty sure a woman who sells her body to any old slob with money isn't exactly one to care too terribly about how a label affects her dignity or anything.
Not that I have anything against whores, mind you. Some of my best friends ... um... never mind.
“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi