It's because Spanish explorers thought that they looked like pine cones, so they called it "pina." Several hundred years pass and some maniac put it on a pizza. It's called evolution, and with Canadian bacon it is delicious.

Intelligence is "knowing that tomato is a fruit"

Wisdom is "knowing not to put tomato in a fruit salad"

Yes, tomato is a "fruit" in the biological sense. But so are cucumbers, squash, zucchini, and many other savory plants. Fruit in the context of a kitchen, however, tends to be on the sweeter side.

Its because 'fruit' and 'vegetable', in their culinary context, don't really actually mean anything.

... Also, just wanna let people know that in the midwest, pickles on pizza are not that uncommon.

Other languages are smarter about this, e.g. German differentiates "Früchte" (fruit in a general sense, including botanical), "Obst" (sweet/sour/non-savory fruit in a culinary sense) and "Gemüse" (savory fruit, salad, roots etc. in a culinary sense).

That said, I like pineapple pizza.

Cos Tomatoes aren't sweet

If fruit on pizza, why not raisins, grapefruit, and lychee?