Well, its complicated. At the end of the day, success determines who is right or wrong. And from that angle, the US were right. Without WW2 they wound not be in the role they have now (for how much longer is another question).
Btw., I didn't mean to say Hitler was stupid. But he (and the inner circle of the Nazi party) was delusional about a number of things. The whole race thing drifted off into a kind of religion, that made them think they can't possibly fail, because they are superior to other people. And especially Hitler believed more and more that everything he orders will happen. Because it was him who ordered it, and he is never wrong. Well, that didn't work out, as we have seen.