Some ask, "Why dispute religion when it does no harm?"
Well, there are many instances where the false beliefs of religion do cause harm.
Here's one example:
A man who is (by all outward actions and appearances) a good person, loses a child in a terrible accident. Being a religious man, he cannot understand why a loving god would allow such a terrible thing to happen to him.
The only way that others can justify this to him, is by telling him that God has his reasons.
Now, more terrible things happen to this fellow. His house burns down, he loses his job, etc.
Now his fellow believers are starting to think that God's reasons are to punish this guy for something! So on top of all the misery being suffered by this guy, he is now looked down upon by his peers as being unclean!
A real life example: when New Orleans got wiped out by hurricane Katrina, many religious fools blamed it on the lifestyles of those living in New Orleans! The holier-than-thous believed the poor people of New Orleans got what they deserved!
This is one small example of why religion should be opposed, and not just tolerated.
More than any other thing, religion breeds hatred.