It's something I've noticed that I find amusing -- anecdotes I've heard from a lot of women who insist they reject traditional gender roles in their relationships, but still waited patiently for the guy they were dating to kiss them, and never realized the irony.

Of course not all of them do that. In some cases they lost patience, at which point they took action themselves, and told the guy to kiss them already.
My take is that, while some guys think its a respect issue, most girls see asking to kiss them as a sign that you have zero self confidence, and that you aren't willing to take any risks.
The advice I've seen from some women for nervous guys is, don't ask, but tell them "I'm going to kiss you now," and that gives them time to refuse if they want without the guy looking unconfident.