Why? If you adher to some philosophy and try to find your path in life then that's good too isn't it? That's a perfect substitute for religion I think.. Why believe in supernatural powers or worship creators if you can find comfort in your inner self?
If you beleive a religon you go ahead and do it, but if you can go without one that's ok too. We'll all eventually know who's right, but right now we all do need to learn how to co-exist. I think that is the lesson we should all learn from this thread (even if we already known it before this thread).