I agree with lots that Harris has to say, but he is completely wrong about this one, and the above diatribe actually contradicts what he has written elsewhere.  You can’t have it both ways, Sam: either religion causes extreme and apparently suicidal behavior or it does not.  King took risks that were not rational when you begin from the assumption that indifferent chance and necessity are all there is to it.  What King was able to do cannot be separated from his confidence that unmerited suffering would win out over both brute force and propaganda because love and not malevolance or indifference is at the heart of the world. 

The confidence that enables one to throw one’s body in front of a gun or a fire hose for an apparently irrational hope that an apparently intransigent injustice is not different from the confidence that enables one to blow oneself up for the same kind of hope.  King was not a fundamentalist and may not have believed in life after death, but he DID trust Reality to ultimately support the downtrodden and his behavior cannot be separated from that trust, which he himself (with a theology informed by Christian existentialism) would have acknowledged to be a leap of faith.