OK, there seems to be a common misconception here that needs clearing up.
American Pizza is every bit as original and valid as Italian Pizza. There was no great big Italian Pizza tradition before American Pizza began; there is a lot of indications that American Pizza was invented first, to be honest, and spread back to Italy.
Italian Pizza is no more correct or authentic than American Pizza is. The Italian ways of eating Pizza, their feelings toward pizza, and their pizza ideals are certainly valid, but no more valid than the American counterpart.
And while there are regional changes to Pizza as it spread across the US to conform with the local ideals and tastes of Italian-Americans in those locations, this does not make those pizzas less authentic or valid than the first pizzas, the New York style or the New England Clam style Pizzas.
Diversity of pie types is a wonderful thing.
And you know what? I’m not even going to judge the places that have really, really wacky and off-base interpretations of Pizza (Seriously, sweet corn? WTF?) because they provide tastes that the local population want and crave. Everyone makes Pizza their own. And that’s a great thing.
So, people from Austria; before you talk about how stupid Americans are for eating our national dish, remember: we blame you for both world wars and hate you anyway. Well, except for Arnold. Who likes Central Ohio Pizza. He’s cool.