Well bear in mind this is post the first black crusade, they are trying to keep the attention on the traitor legions. From what ive understood, its believed that the first black crusade was the last hurrah of the traitor legions after the horus heresy. So the imperium is content to ignore them in face of other problems, and that complacency is whats bothering the ordo malleus inqusitors.
Remember, the Emperor himself granted the Malleus remit to the inquisition.
Last edited by Brother Lucian; 04-03-16 at 12:38 AM.