I did the Rogue legion campaign. The whole organization was screwed up, but none of the non-legion spies had any idea. Even though that's their job. I'm not blaming them for an inevitability, but their failures during Legion have more to do with people dying than Wrathion; and yet we get nothing from Anduin in the way of "throwing blame."
Edit:
I'm aware what sets off the purging of SI7 is because someone does figure it out and gets killed in the Sewer.