Here's my perspective.
It is sometimes the job of a police officer to take out their gun and shoot someone. They are expected to size up situations, often very chaotic, potentially life-threatening situations, in a split second and make a decision if they should shoot or not. That being the case, while they should have absolute accountability and full training, their poor decisions, made in crazy situations, should NEVER be equated to a common criminal who never had the business to have a gun in the first place.
I don't think it's fair that if I make a mistake doing my job, I get reprimanded, while if a man who puts his life in danger to protect me makes a mistake, they go to jail for life. Obviously, their mistakes have much bigger ramifications, but there still should be a level of leniency in the picture.