No rational atheist (or “New Atheist”) holds religion accountable for every idiotic or unethical thing religious people do. We blame a religion only for what its adherents do as a direct result of its doctrines, such as opposing gay marriage or killing apostates.Harris is saying that failure to believe in God is a single item of belief that does not have uniform consequences for all people who hold this belief. However this is not true. Certain other beliefs and behaviours are logically consequent for any single belief. While this may not be universally the case for every person, it is the case for groups of people who hold a belief. Do other beliefs and behaviours logically follow from any particular belief? Yes they do. Atheism may have no other doctrines but certain things follow such as the idea that consciousness has a naturalistic explanation.
Atheism has no doctrines. It does not demand that a person do anything, or refrain from doing anything, on the basis of his unbelief. Consequently, to know that someone is an atheist is to know almost nothing about him—apart from the fact that he does not accept the unwarranted claims of any religion.
Atheism is simply the condition of not believing in Poseidon, Thor, or any of the thousands of dead gods that lie in the graveyard we call mythology. To that extent, everyone knows exactly what it is to be an atheist—he has simply added the god of Abraham to the list of the dead.
If a belief in astrology were causing people to go berserk—to deny medical care to their children or to murder unbelievers—many of us would speak and write about the dangerous stupidity of astrology. This would not be bigotry or intolerance on our part. It would be a plea for basic human sanity. And that is all that an atheist’s criticism of religious tribalism and superstition ever is.
If you understand this, you will recognize any attempt to blame atheism for specific crimes, great or small, for what it is: A fresh act of religious demagoguery.
More importantly is the assumption of atheism here. If atheism happens to be true then atheists who are nasty may be just nasty, but not because of atheism. Consider the alternative assumption though, that theism is true. If theism is true and there is a God, a creator who owns us and we are accountable to. What does this say about those who do not believe in this God. The position of atheism in this scenario is not neutral, it is a position disbelieving the truth. It is also a position of refusing to acknowledge God's authority. Disobedience to God in other areas is also more likely, especially the more vehemently an atheist rejects his creator.
Assuming no God, the atheist is more likely to have a specific set of views and behaviours (based on his atheism) than the person who believes in God. Assuming there is a God, then the atheist is more likely to rebel against God in many ways.