Evolution and Immorality
James C. Rocks
Young Earth creationists, attempting to disprove any theory that disputes their belief that the Earth & universe were divinely created, often use arguments that attempt to demonstrate theories opposing theirs as immoral. Darwin's theory of Evolution (or Neo-Darwinism as it known today) is claimed to be the cause of violence, racism and other forms of immoral behaviour.
The favourite target for such criticism is communist Russia ... the ultimate example of the misery, tyranny, terror, immorality, and inhumanity that can result when, as many outspoken clergy will claim, atheism dominates a society.
The Ku Klux Klan (actually two distinct, secret, societies) are whites only, Christian religion organisations ("God is white"). The KKK exists to maintain "white supremacy" and, in the 19th century attempted to achieve this by strange disguises, silent parades, midnight rides, its mysterious language and commands all playing upon (mainly black) fears and superstitions. The riders (dressed in flowing white sheets, their faces covered with white masks, and with skulls at their saddle horns) posed as spirits of the Confederation army returned from the battlefields and were often able to achieve their aims by terror alone. They also used whippings and lynchings not only against blacks but also against whites seen to be in any way "pro-black". The Klan was particularly effective in systematically keeping black men away from the polls so that the ex-Confederates gained political control in many states and forced Congress in 1870 and 1871 to pass legislation to combat them. The Ku Klux Klan was re-founded in 1915 by William J. Simmons (an ex-minister) and to its "white supremacy" added an intense nativism, anti-Catholicism and anti-Semitism whilst stressing its fundamentalism in religion. After World War II, led by Dr Samuel Green, KKK became responsible for violent attacks against blacks and civil rights workers in cities throughout the South, including Jacksonville and St Augustine, Florida, Birmingham and Montgomery, Alabama and Meridian as well as Mississippi. Currently, there is a resurgence of support for the Klan manifest in its new "evangelist" David Duke of Louisiana.
Adolph Hitler was a devout Christian and his beliefs were key to the reason he and his Aryan followers carried out ... included in this was the creation of camps to process humans (Jewish humans & others) from involuntary admission to extermination in an efficiently managed, factory-like manner.
There are others.
Discussion
Apartheid is a political system (principally South African) based on Christian principles. It was one on the most brutal regimes of this century where every citizen had to be classified as a member of a particular race. The ruling race was white (at more than 5 million) and almost exclusively Christian. They (the whites) ruled over the remaining 30 million plus blacks, 3 million plus "coloured" and over a million Asians. Each of the non-white "categories" had several sub-directories, such as "Zulu", "Pedi", "Tswana" and "Xhosa" (black) and "Cape-coloured" and "Griqua" ("coloured"). These categories dictated where you could live, what education you could get, what work you could do, who you could marry and what political rights you had. From 1945 to 1991, 11-12 million people were arrested for violations against these regulations.
Law separated blacks and whites. The blacks lived in their own parts of town, called townships, strictly segregated from the whites. Since the first whites settled in South Africa, they had believed that the blacks were racially inferior and couldn't be expected to live like Europeans, but this policy wasn't pursued to its cruel conclusion until the election of the National Party in 1948. They issued a series of laws to keep the blacks down and away, but available for work. The National Party stayed in control until 1994, when ANC won the first free election.

Conclusion
More & worse violence has been done in the name of religion (including Christianity) than, arguably, any other factor on this planet.
References
- "Holocaust" Michael Hakeem, Ph.D (1992)