NEWSFLASH: There will always be extremist elements within movements, regardless of respective worldviews for the simple reason that human beings are the ones running it.
If you want to continue pointing at us, as to you, we're the most dangerous? Please look up the Eugenics program in the US which inspired the Nazis to do the same. And it wasn't begun by Christians but by Atheists who were more than enthused by Natural Selection.
Social Darwinism soon emerged as the accepted belief amongst Atheists and Agnostics, as the Rich and the Poor were thus, not due to hard work or inheritance, but because they're more evolved than the rest of humanity so they naturally rose to the top of the socio-economic ladder.
And it didn't take long that Progress (in view of how far mankind has come, from sticks and stones to industrialization and Enlightenment) can also be applied to human biology. What if, through medicine, can not just cure minor ailments to plagues but eradicate undesirable traits in human beings.
To be fair, not all supporters of Eugenics are racists (and some churches, who've accepted Darwinian Evolution were part as well), but the science then were not as it is today as Africans were believed to be less intelligent than their European counterpart due to skull size, but Racism was certainly one of the driving force of the program.
And so, from the 1920's on, the Eugenics program was in full force with the help of the Federal government (as they were conviced that it was part of the eradication of disease). Both Black and Whites were targeted for sterylization, isolation, and experimentation as those who are considered "Feeble-Minded" such as the Prostitutes were fixed to where they could no longer give births, and at worse, African Americans were deliberately infected under the guise of disease prevention.
The Nazis in learning about the US program ran their own and begun with the Mentally and Phyiscally disabled; which then evolved to the Final Solution "to the Jewish question."
