Try reading cycle of hatred, where an orc tells his story of how he was made into a slave by the humans after the first horde fell, how he was pissed and shat about by his masters while they treated him as nothing less then an animal.
To an orc, this is worse then death. From an orcs perspective, it is worse to live in shame then die in honor.
Now, try and tell me why you think its all about one side in this debate and how humans can't be accountable for anything against the horde?