The USA policing system is very complicated. It's not like the UK. There's not one system in use. There's all different sorts with different powers training etc all over the place.
I appreciate that it's different in different states, and not all would employ the knee on the neck. If it is a recognised restraint though, unless Chauvin didn't do it properly, as presumably as he was taught to do, then really, as something that the police do as part of their job, he shouldn't be prosecuted for it. It makes me think of the st John ambulance training I did (it's sort of the same but clearly different in application) and I was told that as long as I carried out the techniques exactly as I was taught, then I would not be prosecuted for anything that subsequently went wrong.
I could imagine a mass walk out from police if they find themselves being prosecuted for something they have been taught to do as part of their job.
As for the racist point. In that case no one can ever say anything is racist unless the person says something. I mean that's not exactly going to happen very often is it.
No. But is it reasonable to automatically assume that they are, as the whole world has done in this case?
If the black people in that part of the world say the police are racist then I take their word for it. They know way better than me.
Maybe so. But it doesn't mean every person that is called or accused of being a racist is actually a racist either. I appreciate that people say as a black person someone may get dealt with more harshly / rapidly by the police. It may well be true. But it doesn't mean that every interaction with the police is racist either. And in the case of Chauvin, and the world watching with baited breath / risk of riots if he isn't convicted, and the assumption that he is racist, even though others have died of the same technique, somehow it all seems a little bit off to me.