Faith is blind. Faith also destroys. It destroys independent thought. It seeks to undermine legitimate scientific enquiry. It demands an end to rationalism. It's divisive: it sets people, cultures and nations against one another. Faith has a long and bloody history of war, torture and abuse.
Hitler was a Christian. The whole repulsive Nazi movement developed out of Christian Fundamentalism and originally had the backing of the Church in Germany. The anti-semitic stance began not with Hitler, but with the church. Hitler's faith told him he had God on his side.
There are many Gods, but only one true God. It all depends on which culture you've been brought up in as to which God is real. For Osama Bin Laden, Allah is the one true God, and Osama's faith assures him that he is fighting a cause for good. Never mind that the vast majority of Muslims disagree with him - he doesn't listen to them, he listens to his faith.
Faith is very dangerous. Faith is what enables young people to fly airplanes into buildings or blow themselves up on the London Underground. They are convinced they have the support of their god, and they can quote from holy scripture to back up their argument. They couldn't do it if they didn't have faith.
How could you persuade a young Athiestic Humanist to become a suicide bomber? You couldn't. He cares about humanity over and above the notion of any superstitious deity, and he doesn't believe in an afterlife. And whilst I haven't heard of any Christian suicide bombers, there are plenty of Christian soldiers prepared to lay down their lives, so it amounts to the same thing. There is no end of evidence of Christians committing appalling atrocities throughout history in the name of their God. You can find plenty of accounts in the Bible itself.
"With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion."
(Steven Weinberg - Physicist)