Essentially, what’s being pointed out here is that Alliance-associated villains are typically not systematized the way Horde-coded ones are - even in cases where this seems like it SHOULD happen, like Archbishop Benedictus.
This is (once again) because the thematic fantasies of the playable factions are self/rightful/familiar vs other/ambiguous/exotic. Villains coming from the faction of ‘self’ (Alliance) will always be written as wild exceptions to the rule because their fiction demands both that the faction be presented to the player as ‘normal’ and that this normalcy is blameless. Villains coming from the faction of ‘other’ are freer to be labelled as typical and natural examples of their culture’s norms because their fiction is under no such pressure to reassure the player of that groups essential innocence.
If you want another reason to think this is terrible than “it’s messed up to sell a game whose playable choices are ‘the eternally innocent white people and their ethnic sidekicks vs the readily-duped savages and their scheming leader’” consider that BfA’s entire plot is the only logical endpoint of this stereotyped stance: the Horde is refused all motivation to fight and the Alliance is given little reason to consider their enemies as anything other than monsters.