Comment by vraivroo

You misunderstood. It's not "Pizza" that was looked down upon in Italy, it was "toppings on pizza".

There are 3 official types of Neapolitan pizza, for example, and none of them have any of what Americans would traditionally consider "toppings".

Putting anything other than tomato sauce, mozzarella, and seasonings on a Neapolitan pie is, simply, "looked down upon".