Richard Dawkins in The God Delusion denounced all religion on the basis of suicide bombers and other obviously crazy people. Anybody can do that, and plenty have. The problem is that it's similar to saying all clowns are evil because some people in clown makeup rob convenience stores.
What would have been actually impressive would be to show, logically and step-by-step, that religion is patently dangerous because it leads to people like Mother Theresa. If Dawkins could show, irrefutably, that the most well-known and best example of Christian goodness was a blight on the world, then he would be saying something worth hearing. As it is, he has cut off the worst end of a long continuum of religious morality, leaving a very large part unaccounted for.
Mokalus of Borg
PS - If he could have done it the other way, I'm sure he would have.
PPS - Personally, I can't imagine such an argument.