This is only a "problem" in Germany because some police recruits and some government officials actually care about far-right extremism in the police. In the USA there is only pushback on this when a photo of an entire class of prison guards doing the Nazi salute is leaked .

In case you were wondering if the article mentions the United States, it only does so while quoting a German police cadet:

Steffan turns to his classmates and asks: "Does that mean the police have a far-right problem?" His question lingers in the classroom, and nobody answers it

Eventually, Sebastian Bartz, another cadet, breaks the silence. As it stands, he says, cadets must take a 2 1/2-year basic training program that partly aims to root out racists. Police in some countries, including the U.S., don't train nearly as much.

"We've spent half a year alone on how to use a weapon, how to arrest someone, intercultural communication — all this paired with legal training," says Bartz. "And we're constantly tested on this for an additional two years. We know our stuff. But in the U.S., you've got officers patrolling the streets after just six months of training."

As a comparison, police officers in the U.S. typically have one-fifth of the training that their German counterparts have. According to a 2016 report by the Justice Department, U.S. police officers participate in basic training (other than field training), on average, for 21 weeks.