This betrayal has tainted their honour in the eyes of the Dark Angels themselves. Given that the event was purely within the Legion itself, and was on a world far from Terra, nobody outside of the Legion knows it occurred. Within the Chapters itself, only the elite veterans are permitted this knowledge - in the modern Dark Angels Chapter, only the Deathwing and senior officers know this secret. The Chapter leadership will go to great lengths to ensure that this knowledge does not reach the Imperium at large, even at times going so far as to disobey direct orders from Inquisitors and cause overly curious individuals to "disappear".
Only the most senior members, known as the Inner Circle, know the greatest secret - that Luther, the great traitor, is still alive and insane, living in a cell deep within the Rock. Lion El'Jonson's body was supposedly never found; Luther claims, in his near-senseless mutterings, that the Lion is near and will return and forgive him. The Lion actually sleeps in the most secret chamber in the rock, his presence known only by the Watchers in the Dark and the Emperor himself, until the time he will awaken and lead his chapter on a new and even greater crusade.