Well to be fair, his lyrics are pretty heavy when it comes to faith and religion. At the end of the day, the man can sing/scream about whatever he wants. As long as it doesn't encourage hate (or other worse things) then I don't care. Personally I'm agnostic but I respect people's religions until they use it as a weapon or means for judgement.
I don't care if he writes Atheist lyrics, whatever floats his boat. I just think the whole "I've been saved, thank you Jesus. Fuck your faith." was a bit childish, ignorant and just straight disrespectful.