A common false argument based in misunderstanding and fear directly blames Darwinism, atheism and evolution for such atrocities as genocide, fascism, racism and the Holocaust. Like most false arguments, this one has some degree of basis in reality, but not of the degree that can support such illogical claims.
This false argument has its grain of truth in the history of eugenics. Defined neutrally, eugenics is the study of human betterment through means of gene manipulation and control. The movement itself is said to begin with Francis Galton, a cousin of Charles Darwin. In his work Hereditary Genius, Galton states his opinion that humanity should be eugenically regimented. Charles’ son Leonard Darwin was Chairman of the British Eugenics Society between 1911-1928, and vice-President of the 1912 and 1921 International Eugenics Congresses, the first of which was an offshoot of an earlier meeting by the predominantly German-controlled International Society for Racial Hygiene.
It is undoubtedly true Hitler endorsed Neitzche’s evolutionary platitudes to incubate delusions of grandeur about a super race in a demoralized and desperate populace. Mussolini, who also revered Neitzche and repeatedly quoted Darwin, held that war and killing were essential for the survival of the fittest, and we all know brutal fascism was the result. Karl Marx asked Darwin to write the introduction to Das Kapital because he felt Darwin had established a scientific foundation for communism. All of this is circumstantial, and in none of these cases can we say the idea was the direct cause of the action, and any believer who argues otherwise must also argue that Jesus Christ is directly responsible for the Inquisition and every abortion clinic bombing or witch-burning that's occurred in Jesus' name. Even so, there remains historically undeniable connections between Darwinism, eugenics, the Nazis, and Margaret Sanger’s Planned Parenthood organization (a typical scapegoat), but again, establishing direct lines of culpability between ideas and actions is a speculative and complex task at best.
Sanger publicized her faith in eugenics to assist in the emergence of what she described as "a race of thoroughbreds." Planned Parenthood’s board of directors included Dr. Lothrop Stoddard, reported Nazi supporter who felt social progress demanded neo-aristocracy and authored unashamedly racist tomes including The Rising Tide of Color Against White World Supremacy. In April of 1933, Dr. Ernst Rüdin, Hitler’s director of genetic sterilization and co-founder of the Nazi Society for Racial Hygiene, contributed an article to Birth Control Review, Sanger's monthly periodical. Rüdin collaborated with Heinrich Himmler on Germany’s sterilization law that same year, an edict that called for the sterilization of all Jews and colored German children. For signs of this influence in America, note that John Scopes' textbook, A Civic Biology, introduces the science of genetics as that of “…being well-born,” dividing the human race into five classes and commenting further that “…the highest type of all, the Caucasians, were represented by the civilized white inhabitants of Europe in America.”
Like most false arguments, there are two polarities. One extreme says, for example, that theism caused 9/11. While it is true we have only one airplane-as-missile suicide bombing reasonably classifiable as theistically motivated, it is illogical to reach the premature conclusion that only theists ram airplanes into buildings. An atheist could just as easily do the same in defense of natural selection and population control. Although he acted on land, Ted Kaczynski might be the most recent example of an atheist that repeatedly blew up buildings maiming and killing people.
The other extreme blames atheism for school shootings, and pre-empting arguments that Ted wasn't irrefutably motivated by his atheism, note that the perpetrator of the Jokela High School shootings was undeniably motivated by his atheism, and more specifically by his belief in natural selection, writing before the deadly spree, "I, as a natural selector, will eliminate all who I see unfit, disgraces of human race and failures of natural selection." This still does not support the argument that atheism causes school shootings, any more than one can support the argument that belief in God causes terrorism.
Thus, arguments connecting the science of eugenics with Nazism or Darwinism are not without warrant or illogical, but by no means do they support the illogical conclusion that Darwinism caused the Holocaust. Anti-Semitism and fascism predate both Darwin and Hitler, and drawing direct lines of culpability is misleading and wrong, no different than blaming atheism for school shootings or theism for clinic bombings. Drawing unfair connections between Planned Parenthood and Darwinism also tends to de-emphasize any positive social action instituted on behalf of Sanger or the organization.
Fanatical extremism and delusions of grandeur are the impetuses responsible for fanatical and delusional behavior, not the subject the delusional fanatic extremely distorts. Isn't anybody that would bomb, maim and kill innocent people arguably wrong, whether they believe in Allah, Jesus or natural selection? Honest examination of life teaches that any race, group or creed can psychotically distort a worldview to justify malicious action, and that no race, group, creed is exempt. Darwinism, atheism and evolution can be ethically apprehended and this is a central tenet of the humanist movement. The untold prophets, witches and freethinkers forced prematurely to their graves certainly demonstrate that gross human atrocities arise under religious despots as well, and the annals of history boast no shortage of such religio-tyranny.