We don't have to deal with constant unwanted advances - we only do the dating thing when *we* want to.
On the other hand, the "first mover" has to deal with the threat of rejection, of even ridicule, in a way that the "approachee" does not.
Being able to successfully make the first move takes courage, self-confidence, communication skills, at least a pretense of extroversion, and charisma. Yes, some of these things can be learned, but they are also partially innate. (And someone who goes looking to learn these skills is likely to find the hideous misogynist "pick up artist" community. Ugh.)
I've approached women and I've been approached by them. (And by men.) It's a hell of a lot easier on the ego to say "no thanks" than it is to be shot down by someone you're attracted to. Perhaps, if you're a charming natural extrovert, YMMV.
Note that "behaving like a jerk", which is the problem here, is orthogonal to "making the first move".