But is he a Christian? No! He's an atheist!
He sees that it makes sense for Christians to share their faith, because if you really believed that there was a hell and that people were going there, "how much would you have to hate someone not to tell them that?" This is refreshingly different from the all-too-common "just get away from me, leave me alone, don't annoy me with your religion stuff." Penn might still disagree with you, but he has the good sense to respect you and your integrity.
Let us pray that more people will come to this position! It is one step closer to being open to the possibility that the gospel might be true.