The reason is because, despite the fact that in our hearts we know that you are lost and will stay lost, and that you insist on denying reality, our brains command us to throw at you as much the logic and common sense as we can. Our hearts tell us to stop because it's useless but since we also have brains and common sense (unlike you guys) we just can't. As long as there will be stupid beleifs there will be people trying to bring them down.
That, and the fact that it's a real scandal that those stupid beleifs have even survived untill 2005.
I would also add that I also do it because it makes me sad to see people waste their lives like that. I mean, it's so stupid it's funny, but at the same time it's really, really sad. They're all like, waiting for something wonderful that will never happen. Kinda like in the new movie "Island" (it's pretty good btw).