In game the only NPC who seems to care about "war crimes" is Garrosh. He tells Sylvanas not to use the Blight, and kills a general who uses a WMD on a neutral civilian druid enclave. No one in game seems to care more that southshore was melted vs. everyone in camp taurujo stabbed to death.
WOW is a "total war" scenario. Garrosh wants to genocide the Alliance, and XXXXXXXXX
Edited: I was wrong, the alliance is for lovers, they would never kill a non-combatant ever. Still I feel constantly saying "ATROCITIES" is a bit much.