Why not both? The worst part about how awful the Warhammer 40k universe is IMO is how very human the Imperium is. They hate the xenos. They hate the heretics.

Why not both? The worst part about how awful the Warhammer 40k universe is IMO is how very human the Imperium is. They hate the xenos. They hate the heretics. They hate themselves, each other, and everything else. Hate! Hate! Hate! An emotion as pure as it is deep! Hate! Hate! Hate! Let it flow, let it run free! —Inspirational Verse, Imperial Hymnal Vol. IV Humans rarely stop hating one another because of a foreign threat, instead we just add more hate to the pile. Quite depressing.