I don't really have any pizza toppings that are "deal-breakers" for me. Smoked oysters on a pizza sounds really weird, but I've never tried it so who knows, it could be amazing. I'm content to just pick off anything that I'm not in the mood for, or order those toppings on the side, or to put them only on half of the pizza. It's only a big deal if you want it to be.
For that guy in our group, though, it feels like this is all beside the point. It's not that he's being "forced to eat pineapple" (because we order them on the side, just for him.) The impression we get from his behavior is that (1) folks wanted pineapple on their pizza, (2) he wants to somehow prove that pineapples 'do not belong' on pizza, whatever that means, and (3) he didn't "win."
Andy, if you're reading this? Stop your ridiculous crusade. I'm ordering a ham & pineapple | ham & jalapeno pizza for tonight's game and you'll never stop me. I'm also lobbying the pizzeria to put this pizza on their permanent menu as "Andy's Favorite" in your honor. It's a small, family-owned joint; they'll probably do it.