Honor, or more specifically she lacks it entirely and conducts the war without it at all. Honor is explicitly listed as something the Horde values in several places, by Blizzard, such as the Pandaren quests to choose a faction.
It's never stipulated that free will was something reserved for the Forsaken. They hold free will dear because violating someone's free will makes them no better than the one who made them what they are in the first place, it makes them no better than Arthas.And further more, she violated freewill of which Forsaken?