There's no XYZ Union Monster, either. Only Fusion Monsters.
I see no reason to accept people using all-caps "XYZ" to mean Xyz. Nobody sane would accept people randomly saying "SYNCHRO" or "FUSION". Why should I accept "XYZ"? It's not an acronym/initialism, and never has been. It's always been a word.
I guess next time someone mentions xyz make sure they clarify that it's xyz monsters with ranks and black backgrounds not the union monsters from electric overload.
Or, you know, just say "Xyz", since that's what they're called.
(Personally, I wouldn't have commented on the uncapitalized one, though your comment was vague enough that you could have legitimately just not realized we had XYZ-Dragon Cannon.)
You what's funny here is that each time people talk about xyz monsters (like number 39 utopia)on this site some little girl has to come by and say that we already have XYZ union monsters in electric overload.