Actually, he has ruined their experience by making life in the house continually subject to his contrived and manipulative "drama", wind-ups, and attempts to provoke HMs into doing or saying something that will get them thrown out. He's even managed to ruin the BB experience of many viewers.

That was a major slip up on his part.
Because by saying that he incriminates himself.
He's pretty much saying that before Cami left he wasn't being himself. Yet in the diary room he gave some cock and bull story about how genuine and real he has been in there.