By explaining to him why you don't want to go to church, were you opening up a dialogue with him, or were you giving him the ultimatum (like this is the last time you are going to explain it)?

If you don't want to discuss anything of the spiritual nature with him, you can tell him so. But you also need to stick to not talking about it with him; that is, no matter how much you want to vent about the people in the church. You can vent to someone else, or to us on PC

I don't think there is anything wrong with you blocking someone who is aggressive, disrespectful of your boundaries, and dismissive of the pain you experienced. Mark's attitude should have been more like, "Okay, I respect your decision, but my door is open if you ever want to talk about it again." I feel that his "care" may have turned into "control" at some point. Whether church people or not, I hope you meet kinder people in the future.