Quote Originally Posted by Mr._Blinky View Post
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Just keep in mind that the Emperor himself was not very tolerant. The Imperium's Xenophobia came from somewhere, and that was the Emperor. In the Horus Heresy novels, it's strongly hinted at and outright stated several times that entire races of xenos were wiped out because they were alien, and entire systems of humanity were cleansed because they would not kneel to the Emperor and/or they were too 'contaminated' by aliens.

In his defense, though, pretty much every non-human faction in the 40k universe (and remember, the Xenos on the TT game make up only a small number of that in the universe--less so than at the start of the Great Crusade) tend to kill, maim, or enslave humanity. The Eldar don't give two craps about humans--heck, they started the War of Armaggeddon that's claimed billions of human lives to save a few dozen Eldar lives. As for the Tau, the only thing that makes them better than the Imperium when it comes to cleansing is that they give you an option to surrender before they blast you to pieces. The Imperium does not.