Racist tendencies and anti-Semitic tendencies are potentially two very different things. It's a scientific fact that many minorities are less intelligent on average (some groups significantly less). Equally, it's a scientific fact that Ashkenazi Jews are on average smarter than pretty much any other group of humans (just look at the absurd number of Nobel prizes that group wins). Nazi Germany wiped out Jews by the millions, an utterly despicable act targeting the best and brightest of German society, so they're very sensitive to anti-Semitism and have special laws criminalizing it in particular.

Depending on what is actually going on, the German government may be criminalizing the publication of scientific facts. We don't know, because the materials published have been censored.

Indeed, this very post may be considered illegal in Germany...