I'm sorry but religion causes a lot of hate and pain in the world, mostly due to extremists. If you go back to ancient times, you'd have an oracle saying whether you should go to war or not and even gods of war to pray to for winning. Although these ancient polytheist religions aren't really here anymore the point is still the same. Belief I can handle, belief is good but sometimes it goes to far and thats when the killling begins.

There is also the issue of religions going head to head against each other. Take the problem in israel and the muslim countries that surround her as an example. Or take Northen ireland and the republic of ireland as an example.

Religious cults steal peoples money and brainwash them, or have them commit mass suicide, your example here is the peoples temple.

Religion has a way of leading to violence and that is why the world would be a better place without it.