I side with the police on this one. The electorate in the United States has become so fucking stupid. They think like children. Look at this as adult men and women who have some clue about what it's like to be a police officer.
The important facts about the incident are that you have five things mixed together that can't be mixed: (1) police officers with guns, confronting a suspect who they do not know (2) who is armed with a knife, and (3) who is behaving abnormally and unpredictably and (4) who is refusing to disarm and, holding the knife, (5) is refusing to obey orders.
I'm not saying that the shooting was justified. What I am saying is that it is always going to be dangerous to hold a weapon in front of a police officer while refusing to put the weapon down and while acting unpredictably.
IOW, it is dangerous to be mentally ill. The dangers of being mentally ill are comparable to the dangers of being totally blind while walking down the sidewalk. Shit happens, and to some extent that's just the way it has to be.
Finally, looking at it in financial terms, making it harder to sue a police officer will make it easier and less expensive to attract better candidates to apply for the job. It could well result in smarter officers who make fewer bone headed decisions under pressure.