The 'right thing' when it comes to demons often tends to come across as the 'wrong thing' in the view of everyone else. If Ken were looking for altruism this story wasn't going to lead him to any.

"Heroic? I wasn't heroic! I was the Black Knight charged with fermenting discord in..."

Crowley paused and glanced around just to make sure they were truly alone. He doubted Ken would give him any real trouble about this but there were others who might have.

"King Arthur's Camelot... But it must have been a different King Arthur. This one doesn't seem to remember any of that."

Or if he did it didn't matter as Crowley had been keeping a low profile.