Board Thread:Warhammer 40k General Discussion/@comment-67.197.44.118-20130216115719/@comment-3258762-20130216121314

It is generally accepted that they are both loyalists and traitors. They do not support the Imperium and fight to bring it down, but only because, according to the Cabal who informed them, when the Imperium falls all else will, and thus Chaos, and the greater evil, will die out from starvation.

So they are said to be "closet loyalists" by the fandom.