dude, how much penn and teller have you watched? might as well say "hendrix wasn't a very good guitar player"... sure, might not be your cup o'tea, but his creative "magic" tricks and devotion to comic rationalism and science are unimpeachable
if god does exist, you have no need to worry, i'm sure penn will be sharing a cell w/ carlin, voltaire, adams, etc (which come to think of it, doesn't sound like much of a punishment at all )