Natural selection...

The other day we talked about why Darwin's views have political flaws. We said one reason was because people do not like the idea that they will be separated into groups and that natural selection would occur. I think Hitler had an idea that related to Darwinism and it is just not morally acceptable with people. You cannot have superior races I think. There are just too many different traits that apply to different people that work for them, that it would be too difficult to pick and choose which traits are the right ones and the wrong ones. Also, Natural selection is a problem because you do not want it to happen to you, and I believe people have a natural inclination to help one another. I do not think natural selection could occur because people would not just sit by and watch their fellow man die.
I think that genocide is very closely related to the ideas of natural selection, and it worries me because when you put the words down on paper you're like" I would never let something like this happen, that is terrible!" but we let it happen all the time. There have been genocides going on for years in different places, and we all say that it is awful, but i feel like we don't do anything to fix the problem.I do not like the idea of natural selection, so am i being biased by thinking that it does not/ would not take place amongst people? I feel like people are naturally good; if this is true, then why do they let genocides happen? What is going on in the world right now? ( Concerning genocide or anything related to natural selection.)