It's not cherrypicking though - it's clearly defined game mechanics and you can check them out this instant if you'd like.
Replay the game, open up the campaign in the editor, see that they're not heroes.
Warlock might be the first proper argument i've heard in regards to WC3, but remember that it is covered by generic DnD classes, which was the other source you (or someone else? Not gonna look it up) convincingly mentioned as serving as a basis for WoW classes.
So yeah, agree or don't but the precedent is simply absent, much like the class is in WoW.