What amigo said was that if religion disappeared overnight, the world would be more peaceful. He said nothing about that all religious people are out there killing in the name of God.
His original premise is quite simple, and true. If overnight religion simply disappeared, one of the giant disagreements among mankind would be gone. Yes, some people would have to learn to comfort themselves without the crutch of religion, but the world would be more peaceful because one of the main causes of war would be gone.
It wouldn't be perfect, and Amigo never claimed it would be, but it would end many ongoing conflicts. Of course, then there'd just be other ones about money, property, etc...