Sorry you didn't enjoy it more. But I wouldn't say it was necessarily aimed at Teenage Boys and UFC fans. You just have different standards for your storytelling then we do. What you saw as forced and contrived, I found flowing and natural. As far as aping Hitler, if your gonna ape, ape the best. Hitler has been aped in one way or another in thousands of stories. And the point of the dialog is that you are exactly right, the heroes didn't have any philosophical differences. They were just used to being the only gun on the block, and were slow to trust others with the same powers. But once they realized that they needed each other, they were able to work together.
What you found annoying about Tony Stark, the majority of us find endearing and engaging. Yeah, he is a smartass. But that is because he is one smart man. Perhaps the most brilliant man on the planet, but he does it with a self deprecating sense of humor. He not only jabs at others, but himself as well.
Again, differing opinions. I am by no means trying to convince you that you are wrong (you aren't necessarily) or that I am righter than you (which I am not). Just stating my take on some of the same things. If we all liked the exact same things, every film that came out would cater to those elements, and therefore, none of them would be interesting or different.