What I have never understood about atheists is the following. For the sake of argument lets grant their basic premise to be true. No God and religious practice is wasted effort. Just people being foolish, OK so why can't atheists just let people be foolish. If it has no meaning then they shouldn't care how others waste their life on it.
I utterly don't understand their militancy. Unless they are so unsure of their atheism they need to constant validation of converting others to their view point.
For every obnoxious atheist who runs around railing against religion and suing to get the creche taken off the courthouse lawn, there are a hundred more who just quietly unbelieve, and are perfectly willing to "let people be foolish". I wouldn't be surprised to learn that there are a few of them sitting in the pews at your church.
Militant atheists do believe in God on a basic level. You don't expend that kind of energy on something you don't believe exists.
They have a deep and abiding hatred of their "father" and simply project it towards God. They are victims of abuse and on some level are angry with God because they see Him the same way they see their tormentor or they are angry with God because of what happened to them.
Their hatred invariably winds up directed at anyone who believes in God. They can't hurt God, but they can villify and malign those who believe in God and religion, and attack God by proxy.