it sends a message that people have a right not to feel creeped out even when the feeling is unwarranted

The word "right" seems to be unwarranted here. It's not clear that people have a moral right not to be exposed to rude or anti-social behavior, but this does not make the behavior any less rude or anti-social. There is such a thing as good etiquette, however minor and trifling it may be when contrasted with genuine ethical concerns.

The legitimate creep or the awkward geek is not any less dangerous because he read Dale Carnegie or a PUA website.

But an awkward geek may unwittingly behave in ways that make people mistake him for a creeper; reading Dale Carnegie is a good way to address this. As for legitimate creepers, it would be nice if they too could reform and stop posing a danger to others; unfortunately, most of them seem to be actively hostile towards other people and lacking in empathy, so this is not a likely prospect.