Who cares about PvP? Unless it's Vanilla PvP when Horde racials were arguably stronger, then it's the most important aspect of the game (even more so when you consider that Alliance had the advantage in PvE then instead, which necessitates that the importance of PvE is to be downplayed as well).
Wait, you don't think a human boi-king explaining to Saurfang (who at the time has already betrayed and abandoned the Horde but w/e) what honor is and then telling him what the Horde is actually about were Horde's crowning moments of awesome?
Please, that's just the tip of the iceberg when it comes to HORDE BIAS. Repeating the same story (of throwing the Horde under the bus, removing its leader, making it collapse on itself and kowtow to human idiot that should have lost the war within a week) is just one of the examples, but there are also HORDE BIAS things like
this here in-game cheese (i.e. Horde characters being able to eat a cheese named after a human kingdom, even if it's one that betrayed the Alliance), the Zandalari Shaman's water totem (blue color is sole property of the Alliance) or, you know, the Horde existing at all. And roughly 43 vigintillion other examples.
Well no, it only works one way, duh. It would be inconvenient to the totally-not-a-conspiracy-theory otherwise.