I disagree about that being the message of the Incredibles. I think it's actually about differences, not superiority. You'll notice that the supers never say they're better, only different, or they'll specifically say having super powers. Also the supers aren't trying to establish their superiority. They just hate not being allowed to help people when they have the power to do so. I think it's about celebrating difference. It doesn't matter what your talents are, or what you look like, but how you use them.
Also notice that the fame of being a super isn't what they want (Mr. Incredible goes to the island the first time and immediately starts feeling better because he's doing what he loves, even though he's not receiving recognition). It's about doing what you're good at, and doing it in a way that helps everyone.
Syndrom from the beginning wanted to be famous, not help people. If he wanted to help people he would have just started being a super-hero with his inventions, but as a kid he tried to attach himself to an established celebrity super-hero. Throughout the movie all he cared about was fame and power, where the supers have power and all they think about is helping people.
The theme isn't that some people are better than others, but that everyone is different in their own way and we should tolerate and celebrate our differences. And everyone should use the things that make them different to make the world a better place, whether or not they get noticed for it.
