My Korean ex- put American on everything also, including kimchi and While I failed to find original post to see what you're referencing, I've also seen the Koreans putting hotdog and fruit cup on pizza.
I grew up on American so I like it. I like the texture and the smoothness. I've met plenty of cheese snobs, Yanks are almost exclusively this. But cheddar is gross by comparison - tastes sour and chalky. Now, pub cheddar is some godly shit as is cheddar cheeseballs, but slices? I haven't found anything better than American. The closest has been swiss, but I can't have it every time. I helped open the Panera Bread in C-burg and grew to appreciate Gouda, but even that doesn't work on everyday sandwich.