A favorite target of theist critics of atheism is Marxism, both in theory and in its practice. Atheist advocacy in 2007, 2008 and beyond requires dealing with this specific theistic whipping horse. Below is my feeble attempt to do so.
Theists frequently cite Marxism as part of their rhetorical challenge or response to atheist advocacy. From the anti-communist advocates of inserting "Under God" into the U.S. Pledge of Allegiance in the 1950s to Pope Benedict XVI this very week in his encyclical Spe Salvi, the negligent, reckless or willful confusion of atheism and Marxism continues its dull, flatfooted, pedantic march, lowering effective IQs on this topic through sloppiness or worse.
The following are a few ways to respond to these common lines of argument.
While attacking Marxism is an entirely fair way to challenge advocates of Marxism, it is intellectually fallacious to attack atheists on the basis of Marxism. It is an ad hominem attack, a guilt by association, against those atheists who do not in fact adhere to the philosophical, metaphysical or political tenets of Marx or major Marxist thinkers, and therefore illogical. If atheists were to argue that no atheists have ever participated in a making or running a vicious totalitarian state, Marxism would be an obvious knockout "inconvenient truth." But what atheists actually argue is that a sound epistemological basis for a belief in a god - i.e. evidence - does not exist. Atheists do not argue - or have never argued in my decades of reading - that atheism is an inoculation from the totalitarian effects of any other ideas other than atheism. It is a classic straw man.
While atheism is an element of most Marxist thinking, Marxism is not an element of atheist thinking. Again, to repeat: Marxism is not an attribute of atheism. Atheists are not Marxists in the overwhelming number of cases. Most atheists today would in fact object to Marxism either in theory or in practice. Marxist governments have often (though not in every case) constructed an institutional or intellectual analogue to almost every element of a theocratic state: censors, ideological witchhunt-style trials, totalitarian spying and inquisitions, shrines (e.g. Lenin's tomb, the Ehrenwache Unter den Linden in old East Berlin, the enshrinement of childhood homes of Tito, Kim, etc.), councils for the propagation (and periodic edition) of dogmas, etc.
Perhaps I have an overly high opinion of American atheists (small "a" EXTREMELY deliberate.) But I strongly suspect that almost every atheist in the United States, other than the 19 Communist Party members who had not yet died of Alzheimer's, cheered when the Berlin Wall fell in the late 1980s, admired theists like Lech Walesa and Pope John Paul II for their fight against Marxism, other disagreements aside. When the then-unidentified Chinese freedom fighter stood in front of the rolling tank in the famous photo and video near Tiananmen Square, who would really believe that U.S. atheists were cheering for the tank?
Most atheists in the U.S. are, implicitly or explicitly, secular humanists. That means they believe in human capacity and individual freedom and rights, not in some fucking proletarian revolution envisioned by a German child-support ducker writing in his madness from London's British Museum in the 1800s. What totalitarian Marxism and totalitarian religion have in common equally repulse secular humanists - totalitarianism and its concomitant rejection of individual autonomy, privacy and freedom of inquiry.
I cannot blame theist advocates for kicking Marxism; my boot is right there with them to administer an old-school beatdown, or as we say in Baltimore "banking", of totalitarian Marxists. But if they think that they are kicking "atheism" when they are kicking Marxism, they need either to improve their intellectual ethics or at a minimum retake Logic 101.
These two paragraphs is a respectful response to Anthony de Jesus' comments below, to whom HAT TIP. For the record, I did indeed read Benedict's Spe Salvi before I commented on it. I had read the Yahoo "blurb" on the encyclical, thought the blurb made no sense, and went hunting, finding the Italian translation and then the English one. My claim that Benedict conflated atheism and Marxism comes from Benedict's claim that the atheism of the 19th and 20th century was a "type of moralism" (Spe Salvi 42) that objected to theistic claims on the ground of natural and or human evil's existence in the world. In fact, "atheism" is not a form of moralism at all, only the philosophical denial or declination to accept the existence of any deity.
The major intellectual force that both made claims about justice and denied theistic claims of the 19th and 20th century was not "atheism" but Marxism. Benedict's description of that movement as "atheism" in Spe Salvi 42 is simply misleading, and his references to Marxist theorists Adorno and Horkheimer (without footnote in Horkheimer's case) do not support Benedict's claim that those Marxist theorists rejected atheism and theism equally. Paragraph 42 follows logically from Benedict's prior discussion of Marx and Marxism in paragraphs 20 and 21.
Pope Benedict XVI has no excuse for his conflation of Marxism and atheism; as a former theology professor and enforcer of Church doctrine against intellectual innovations, he knows exactly what he is doing when he conflates "atheism" and "Marxism." Benedict has never attacked theism as a whole for the specific theistic grounding in Germany for National Socialism - from Luther's program to torture and kill Jews and expropriate and destroy their individual and collective property, to the explicitly stated intention of Hitler - a Catholic in good standing without excommunication until his death - to persecute both atheists and religious dissenters and freethinkers like the Jehovah's Witnesses and the Freemasons, to the standard belt buckles of the Wehrmacht proclaiming not "Gott ist tot" but "Gott mit uns." Blaming Bahais or Unitarians or the largely Christian Danish resistance or Hindus - i.e. other theists - for Nazism's theistic roots is unfair.
You would think that Benedict - a draftee into Hitler's antiaircraft corps as a teenager - would have considered this. But being Pope, like "love" supposedly, means never having to say you are sorry unless you want to, I guess.