I think it is for a few reasons:
1. Religious discussions are fun. Whether that is because the person is seeking validation, wanting to prove a point, wanting to bash someone else, or otherwise.. it’s just plain fun. It is a topic that is potentially (depending on your point of view) more important than any other topic.
†. Some atheists may actually retain an open mind towards the subject and want insight into why believers believe as they do. Perhaps they can sense (on some subatomic level) that there is at least a possibility that believers aren’t crazy.
Matthew 7:7–8
“Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you: For every one that asketh receiveth; and he that seeketh findeth; and to him that knocketh it shall be opened.”
D. There are a few (on every side) who approach the subject with a sense of narcissism and elitism. These few enjoy a verbal tussle in which they perceive whatever version of victory they require in order to sate them. Ironically, this sort is largely insatiable.
§. Let’s just call this “other”. There are those who enjoy being assholes. There are those who are curious, insightful, thoughtful, and rational. There are those who want to play devil’s advocate. There are those who know that fluther is largely a non-religious, liberal forum and enjoy being on the fat side of the lopside. There are those who are bored. Those who are angry, sad, or ignorant. Those who are petty, pompous, pedantic, or pimple-faced (just to round out the “p” words), and everything in between. There are even some who fall into the † bullet but don’t want to admit it (neither to themselves nor others).
» <—- no reason for this.. just started having too much fun with the alt+codes.