This comes up a lot, I've seen, so I'd like to discuss it.
Some Christians say that social darwinism is atheistic and was the cause of the Holocaust. Naturally, I doubt very much the former, and the latter is debatable I'm sure. But, I'd like to talk about Social Darwinism itself.
I don't think that the idea of Social Darwinism is evil in and of itself, and I think that people using it to justify acts of murder and evil is not the fault of the idea itself. It's like the old "Guns don't kill people; people kill people" notion. Even if a consequence of Social Darwinism is to people using it to kill is true, it is no more the fault of the gun that some guy picked it up and pointed it at a another person and pulled the trigger.
And, in some ways, I think Social Darwinism is true. Like in the job market. Obviously if you don't work and have an education you will have a difficult time to "survive" in society. Now, obviously, I don't think Social Darwinism gives anyone the right to start killing people who are "inferior" or "weak", but obviously the ideas of Social Darwinism aren't that positive or nice sounding. But, naturally, that doesn't make it any less true.
Our job on this Earth, is to take care of each other. Something that we have ultimately failed at doing, hence why we are so miserable.