I think men feel a little indignant and offended and threatened when women act as we feel we have the right to, that's when we belittle them and call them sluts. It stems from age old inequality and truthfully, there's nothing much wrong with a bit of screwing around. It's more about the mindset - when we guys think of a girl who is craving some man meat, we are mentally adjusted to lose respect for her. But if we think about getting some booty and become slaves to our lust, we view that differently for some reason. I have had some really bad thoughts about girls. Hell, I have done some dirty things too. But strangely, it's all OK if they are doing it with you. If they're doing it with someone else, that's another matter! It is rather hypocritical.