This is sort of related I guess; but the reason I no longer play Warcraft III multiplayer is because of DotA. Every custom game in the list is a DotA game, and I just hate it. Not even a measly tower defense is available for play. Everybody fawns over it and it kills every other custom game.
Naturally, this pisses me off because there are plenty of other, better custom game types that don't get any action whatsoever. Ugh.
Even the people in the freaking chatrooms go on about it; "Hay bruh, dota?"
Anyway, I have a friend like the one you mentioned, though I suppose it's more with the entire franchise than just one game, and that's Halo. He believes no game series has a deeper narrative, richer gameplay, a better online community, stronger main character - both personally and physically of course, etc., and I can't convince him otherwise.
Tis facepalm worthy.
Now if you'll excuse me, I'm off to build a custom game in WC3 World Editor and add functions that will allow for bots...