One of the more recent lies I have begun to hear is that the efforts of the Nazis to exterminate all those with Jewish ancestry was an outgrowth not just of their alleged atheism (a lie) but also of their "belief" in evolution. Once again, this is obviously a lie and anyone who knows even a little about these subjects knows that it is.
You will hear this outrageous nonsense exclusively from creationists--no one else would make such a claim. The culprits must be those who think the idea of evolution is evil. Their claims show not only a dismal ignorance of history but of evolution as well.
Simply put, evolution is the idea that different species will result from the different conditions that various populations of plants and animals have to cope with in their various habitats. The conditions in which animals and plants live will cause some of them to thrive and reproduce in greater numbers than the others. This "selection" as a result of natural conditions is called natural selection. "Selection" is not an accurate term, of course, because it implies an agent with some sort of consciousness, which is not the case in this context.
The selection is not random--quite the opposite. It is brutally precise. Only those individuals with the right characteristics for their current environment will survive. The process is so brutally precise that more than 99% of all species that have ever existed are now extinct.
What Darwin theorized was that selection by nature could, with time and a sufficient number of changes, cause different species to result. That is why his work is called "Origin of Species". It was well known before Darwin that different conditions or artificial selection could change a population. What Darwin added was the idea that this process when imposed by nature over a long time explained all the various, wildly different species that we see in the world.
The actions and policies of the Nazis were based on artificial selection--not natural selection. Artificial selection, otherwise known as selective breeding, has been around for thousands of years--ever since the dawn of agriculture, before the dawn of recorded history. With artificial selection a human selects which animals will survive and reproduce. This is done not to cause the origin of a new species but to improve the characteristics of the plants and animals that the human doing the selection has at his disposal.
Likewise the Nazis were artificially selecting those individuals they deemed superior and killing those they considered inferior in order to bring about what they thought would be an improvement in the species--not the creation of a new species.
Creationists are, frankly, lunatics. They are absolute proof that religion is a form of madness that leads to the rejection of logic and evidence. Arguing with a creationist is a waste of time--even more so than arguing with other types of believers--and can even be quite dangerous to you. The danger doesn't come just from an immediate, physical threat. If you try too hard, you will find yourself targeted by the person's entire church--after he tells them all what an evil person you are. If that happens, there is no lengths they will not go to "do something" about you. (They may not engage in physical violence in most cases, though even that is not impossible.)
What you can say, and should say, is this:
"That's a total lie. The policies of the Nazis were based on artificial selection, not natural selection. Furthermore, they weren't trying to exterminate a species or start a new species, merely change one a little."
They won't get most of your meaning, of course, because they haven't the faintest idea what evolution is, but they might get just enough to realize they are off base. One of the things that you can always say to creationists, in this context or any other is:
"You obviously don't know what evolution is. Maybe you shouldn't say anything until you have researched it in objective, reputable sources. Otherwise, you run the risk of looking foolish."