Other than that Trump story with Palin, the only ones I’ve seen eat pizza with a fork and knife are the Brits. They also used to (haven’t been there recently) do the same with hamburgers.
I was stationed in Sicily in the mid-70s. We’d visit a genuine AMF bowling alley in Catania for fun and food. We’d bowl, then move to the pizza restaurant inside the alley. This place was swanky...white table clothes, nice china and silverware, dressed up waiters. We’d order pizza and eat with the silverware as the locals around us were doing. Re-visited Sicily with the family a number of years later and the pizzeria was still there...just not as fancy.
At a different location, I did get chastised for cutting spaghetti up with a knife and fork for the youngest child, though. I deserved it!