He has made it obvious throughout the life of the show that he would not be content if Joe did not receive his vindication.
Even though Joe was obviously not going to get away with anything, he was undoubtedly going to wind up in prison since death is simply too good for him.
“The concept needed to come to a close, the writers, me, everybody involved — the fans — we needed to bring this man to his rightful end.
And I think we did so,” Penn stated in a recent interview with Extra TV, reinforcing this mentality.
Penn said, “It was as though I couldn’t sustain the rage anymore, couldn’t sustain the levels of artifice with him, just all of it,” in an interview with the Guardian regarding Joe’s demise.