I think the pressure is getting to the police. Knee-on-neck and hands-around-throat are both over the top, unless the civilian is armed and resisting.
The pressure must have gotten to them several years ago. Here's a 2014 newsclip of a Knox County, TN deputy that strangled a handcuffed, compliant suspect.
You can see he asphyxiates and drops to his knees while the arresting officers do nothing.