The person seems to have a real chip on his shoulder regarding religious beliefs. Perhaps he needs to spend a bit more time practicing what he's preaching. I also think that perhaps this person might be emotionally immature (or else why send and e-mail like that, so very different from his adult sounding posts in your journal) and may be broadcasting his personal dissatisfaction onto you.

You know that I'm pagan, but you also know that one of my key beliefs is in tolerance. This person has none. Don't waste the time of being angry with him; you only feed his justification and waste precious energy that could be directed elsewhere.