I'm gonna be hated by all woman-kind now, But I agree with legend.
You just meet different guys, some are like that some are not. And women have types they fall for, and if they're commitment phobics, then you're gonna build up ideas that all men are like this and therefore, this is how stereotypes are created.
It's the same with women really, people who wanna sleep around and experience everything (so to speak.) And others seem to have found 'the one' and just settle down instantly.
(and yes, for the record. I am one of the latter)