@Edixo Aren't a fetish mean every single little (even the less/more obscure) things that sexually arouse you... rather than "anything that isn't a normal hetero-cpl", heck you've probably heard of "glasses fetish, cat ear fetish, muscle fetish, hair fetish, s...c...a....t, coprophagia, 腹パン(hara-pan)", etc from a hetero cpl and that in itself is a fetish if it arouse you sexually. (mind you the last 3 is among the more obscure one which is rather... common, I guess).
And I don't think those only apply in Japan... afaik, the term itself is there but isn't being used and discussed as openly in society normally (like, duh... imagine your boss/co-worker came up to you suddenly talking about their fetish as a standard topic for chitchat)
and I think a "homosexual cpl" is a rather common fetish nowadays. (even more so in a fandom culture, especially in Idol/anime centered culture) it may or may not refer to fetish depending on what the term "homosexual" is used in.. fetish itself is not limited only to "anything that IS NOT a hetero cpl".