Re: The most certain are the least likely to be correct.
Even if you put aside the question of truth, the question remains: "What are the implications of what you believe?"
The Crusades and the Inquisition both come from a corruption of values - the church institutions took on the values which were opposite to those of the religion. I suspect this was mostly due to the acquisition of temporal power, whereupon they became like all other greedy, power-seeking, money-grubbing organisations. However, at least the basic values contradict this behaviour. The old testament is full of prophecies of doom which God pronounces on his own people because they have become like everyone else around them.
The Muslims appear to have started out on the warparth and the Jews got lost in legalism, bringing down their own God's curses upon themselves. Buddhists will tell you that pain is all in the mind and Hindu's see little to be gained in interfering with karma - the universe's way of judging wrong-doing which ensures that whatever lot in life you have is deserved.
> Oh, and who said that you need a religion so you can have morals?
No you don't need religion to have morals, but to have morals as an atheist is irrational. In fact, if you believe in the genetic machine, your personhood is purely a product of your environment, like the sand dune shapes in the Sahara or the melting ice (or otherwise) at the poles. Any concern for your children's welfare in the face of AGW is just genetic programming and has no intrinsic value. You have no more freedom of choice than an ice-cream machine and even changing your mind is just a result of your genetic programming. Sure you can look after the poor and the homeless, but what is the reason? Surely that is going against evolution, the survival of the fittest - you are diluting the gene-pool with failed material.
I have to laugh with irony when people trot out the crusades as an argument against religion, conveniently disregarding the millions more killed during the least religious and scientifically advanced 20th & 21st centuries. Conveniently ignoring the fact that under atheism, there is no intrinsic curb on my hatred and greed. I fight for my genes to get ahead - sometimes I cooperate, when no-one is looking, I don't have to. I just throw it into the pot and claim its up to history to judge.