I have never understood why Derek Chauvin was charged and convicted of the murder of George Floyd

I have never understood why Derek Chauvin was charged and convicted of the murder of George Floyd.

From my understanding the police in the USA were trained to put a knee on a persons neck, so presumably he was only doing what his training had told him to do.

Also some sugest the jury felt they had to go guilty or be a target of people. Not sure if this is true, but if a single jury member ever states this then I fail to see how this would be a safe conviction.

It always felt to me that Derek Chauvin was a sacrifice for political reasons.

Link: https://www.hennepin.us/-/media/hennepinus/residents/public-safety/medical-examiner/floyd-autopsy-6-3-20.pdf