if u exclude cata, his story is consistent, so he does go out doing what he believes, even if what he believes is wrong
however
we also have confirmed lore answer that Garrosh did regret his actions in MoP, and if it wasn't for that bronze dragon he would ask for repent for his actions, so probably - like cata - half of lore team didn't get that memo because while they work in same building in same department in same fucking office, half of lore team is busy smoking weed it seems to notice anything other team does
because that's how a retard team like actiblizz lore team works sadly