Why dumbfounded? Various flavors of this attitude have been around forever; the classes, races, and builds change, but the "y u hatz meh?!?!?!?" is everywhere, pretty much on every game ever.
Some of it is loosely true-ish: DM/dev has a vision for a class that is dramatically different than the player's vision, friction ensues, and people get passionate (rather a few of my posts back in the Rogue Wars were infraction worthy, for instance). It isn't hate, though, it's just a different vision. Unless it differs from mine, on my fave class, in which case it's hate.