Let's take the pizza out of the owen. Fresh, steaming hot. But what are those pineapples doing on top of it? They don't belong to a pizza. At least according to my Italian friend who is paramount about the matter. And I have a pretty good impression he's not alone.
I'm not a huge fan of pineapple on pizza myself either. I like a few pieces of it on top of it, but not too much. And I can definitely live without it.
And if somebody things pineapple is a weird topping for a pizza I've got some news to tell you: how about beetroot, strawberries or chocolate? Yep, I have seen them all and I'm pretty sure somebody somewhere has come up with even stranger toppings.
And it's not just about individual topping. Any one ingredient can work just fine alone. It's about what you combine them with. I might be a poor judge on this as I'm somewhat famous coming up with strange food combinations, like pickles, salami and caramel sauce on top of a chocolate chip cookie. But everyone to their taste.
Anyway, pizza is such a great invention that maybe we should respect those Italian and keep the pizza as it was intended: but which one of all those competing "original" ones?