"It is said that science will dehumanize people and turn them into numbers. That is false, tragically false. Look for yourself. This is the concentration camp and crematorium at Auschwitz, this is where people were turned into numbers. Into this pond were flushed the ashes of four million people. And that was not done by gas. It was done by arrogance. It was done by dogma. It was done by ignorance. When people believe that they have absolute knowledge, with no test in reality, this is how they behave. This is what men do when they aspire to the knowledge of gods.
Science is a very human form of knowledge. We are always at the brink of the known, we always feel forward for what is to be hoped. Every judgment in science stands on the edge or error, and is personal. Science is a tribute to what we can know although we are fallible. In the end the words were said by Oliver Cromwell: "I beseech you, in the bowels of Christ, think it possible you may be mistaken."
... We have to cure ourselves of the itch for absolute knowledge and power. We have to close the distance between the push-button order and the human act. We have to touch people."
-Jacob Bronowski, The Ascent of Man, (passage spoken at Auschwitz)
Darwin was a progressive - while he may have been somewhat racist, he was certainly much less so than other Englishmen of his time. This says a lot about him, that he would be progressive.
Hitler was a racist, evil tyrant whose ideas are mostly founded upon Martin Luther's 'supreme plan'. If he did base anything of his plans upon the Theory of Evolution, it was based upon a severe misunderstanding of it.
You do not draw an ought from an is, and I apologize, but nature doesn't reform itself around our ideals, simply because we will it.