Not that I think it will have any effect whatsoever on some peoples ad nauseam use of this fallacy... it is at least worth a try.
Wasn’t Atheism Responsible for Most 20th Century Atrocities?
The important part of any discussion as to whether a belief system has “caused” tragedies in the past or will do so in the future must be based on the logical connections between the tenets of the position and the resultant actions of the position’s holders. We can yell at each other all day that Hitler was a Catholic and Stalin was an atheist, but it doesn’t matter; the fallacy at hand is called “false equivalence.” It is a result of implying that because one trait is shared between two items, so must another, e.g. “Stalin brushed his teeth, and killed millions. Obama also brushes his teeth. Therefore, he is likely to kill millions.” This is obviously silly; they may share a trait, but one must make a direct connection between tooth brushing and the conclusion being drawn, killing.
Similarly, when one says, “Stalin/Pol Pot was an atheist, and so are you. Therefore you will also do immoral things,” this is just as silly as the tooth brushing argument, until you prove that atheism leads to immorality in the first place.
So, the introduction of Stalin is just a pointless emotionally-charged debate tactic.
In truth, there is no connection between immorality and atheism. It is just as logical to follow “I don’t believe in God …” with either “ … therefore I will make this world as moral and happy a place to live as I can, because I know we all only get the one chance” or “ … therefore I will not be afraid of hell and likely commit murder.” The assumption that only the latter is true is enormously insulting. I would hope that the fear of punishment is not the only thing standing between you, dear reader, and a murderous rampage.
On the other hand, the connection between many religious texts and immoral action is much easier to make; most of the major, proselytizing religions have textual aspects that suggest believers are superior to non-believers, or that command believers to convert or conquer non-believers. Atheism has no such elements. So next time someone says that atheism will logically lead to violence, remind them of the importance of 1) the logical connection between ideology and action, and 2) the dangers of throwing stones while living in glass houses.
--snip--
A worthy attempt, my religious comrades, but I am afraid that is simply not true. This is because there is nothing substantive about atheism: All it is really is a lack of one belief, a belief that god(s) exist. Therefore, innumerable belief systems may be consistent with atheism. To put the point strongly, an atheist is just as likely in principle to favor communism as he is to favor democracy or aristocracy.
Let there be no doubt: It was totalitarianism and human malevolence that wreacked atrocities, not the lack of one single belief.
http://www.dailynexus.com/2012-02-22/wasnt-atheism-responsible-20th-century-atrocities/