Why are Germans so racist against turks?

How come Germans are so racist against turkish people, while nations like the USA do not seem to have any prejudice against them. I mean next to the same old excuses of they do not speak the language,they wear headscarfs and did not integrate. One would think the germans learned from their mistakes in the past? I thought we are in the 21st century and does not matter what anybody does the world is going to mix and one day we all be the same.