I fully understand why they needed to restrain Floyd. He was a big dude, and clearly under the influence of something serious. I think most cops would be taking precautions as if it was PCP. In this case it was a speedball, but you want to be careful with that, too.
What is harder to explain is why Chauvin lacked sufficient situational awareness to realize that Floyd had arrested about six minutes into the situation. Maybe he was concerned about the trainees interactions with a possibly hostile crowd. Dunno.
I’m expecting the defense to bring up all of those points, and even with the corrupt Ellison as prosecutor, this isn’t a slam-dunk case.
My best guess is they had time to run his rap sheet and saw his previous violent offense[s]. Still, they had Floyd cuffed in custody and no matter what he was on,, 4 cops are enough to control him. Been there done that with a large drunk Marine. It's difficult, but can be done without the knee to the neck. Just got to tussle enough to get the leg irons on if they still want to fight even being handcuffed. That Marine apologized to us the next day by order from his Commanding Officer.