What's interesting to me is that there seem to be a number of "Hawaii" dishes (involving pineapple) that all seem to date back to roughly the same timeframe (1950s) but seem to have very different origin stories.

For example, "Toast Hawaii" appeared in Germany in 1955, consisting of a slice of toasted white bread, one or two slices of cooked ham, a pineapple ring, a slice of processed cheese and a cocktail cherry, baked in an oven. Interestingly, I've read that that dish may be derived from an American "grilled spamwich" (but spam was not availble in Germany at the time). Likewise, "Steak Hawaii" (as well as "Schnitzel Hawaii") involves baking with pineapple rings and cheese.

I'm guessing someone somewhere associated cheese and pineapple with Hawaii in the 1950s as part of the general obsession with Hawaiian-inspired culture (e.g. tiki torches, fake lei garlands, ukuleles and luau-themed garden parties) and it caught on as an "exotic" twist on home cooking internationally (despite Hawaii and pineapples otherwise having no clear relation).

That's a version of the Hawaiian Pizza that might not be a subject of debate.