I personally find it annoying when religion is brought into things, as it;s something everyone has different viewpoints on or may have none at all.
Everyone can believe what they want. Though my mom is a christian and I've been to church, I'm not religious. However, I respect one's beliefs, and sometimes belief differences can start an argument. That is, if you're an asshole who shoves their beliefs into other's faces, yell at them when they say "Hell" or use God's name in vain... Those guys are jerks. But let's not go there right now, we're talking about banning religious discussion.
I don't have too much of a say as I haven't seen too much of anything and if I have, I must have forgotten about it, but I can see how it's annoying. All arguments, mostly petty ones, are annoying. Ones that are meaningful, helpful and utilizes all viewpoints and respects them aren't annoying and should be what's going on. According to what I've read, every religious argument ends in a bad tone. However, we don't need to ban religious arguments, we can tell people to not be rude... But that'll never happen, not on here. People are just so ignorant of other's ways they'll offend everyone to get their way, even when they say they're nice or act nice.
All in all, do I agree on banning religious discussion? Not really.
Is it needed in this forum? Yes, because unless some magic fairy comes by and makes everyone super nice, these arguments are going to end up being what finally destroys our community. If not it directly, then it'd be a contributing factor.