Not all food that gets cooked on a pizza needs a fridge. But either way you’re skipping the point. it’s literally leftovers combined, with or without a fridge. Probably even more so without a fridge if food goes bad faster.
The point is it’s a peasant food made of literally anything because scarcity.
So in all fairness to to the benefit it provides there should be no rule that there has to be a pineapple or not.
If they did they’d be a classist bigot not worth fighting. pizza is peasant food invented not for taste but to not starve. If you’re going to so low to gatekeep fight someone for that, that is definitely on the wrong side of history.
They even have a flavor in most restaraunts called sweet and salty which is just sugary syrup added to whatever savoury sauce. So it’s not like it’s an under represented flavour either. Like I get some people have a simple palette that can only handle one flavor at a time. Maybe they can learn to accept all of the rest of us who like combining flavors.