I absolutely HATE pineapple or any other fruit for that matter in my food, but I also don't particularly enjoy desserts and would much rather have some extra bites of food.
To me sweet tasting things do not belong in food if they're noticeable, so in my world pineapple does definitely not belong on pizza or any other food.

I will however concede that it's completely okay that other people enjoy it, hell it's fantastic that people enjoy different things otherwise we'd never have any new ideas pop up!