Yes, when you enforce laws, some people are a-holes and escalate to unlawful violence. Sometimes cops, sometimes civilians.
The appropriate reaction to make sure that isn't tolerated either, to improve police-community relations, to train police better, and to review whether we need to update laws to match consensus on expected human behavior.
The appropriate reaction is not in a hundred miles of "oh, well, gosh, do we really need to enforce laws anymore? Someone might get hurt!", and the forum is a worse place for tolerating that mentality.
Now, to be sure, there are many laws that fit the last category above and should probably be scaled back for being petty and kafkaesque. But, "don't wake up a million people around you for your own personal thrills" does not make the list.
2. No human endeavor is perfect. I am willing to accept some tragic mistakes in exchange for the prevention of crimes and the dissuasion of criminals.
2. There is no evidence that any prevention of crime was gained in exchange for the deaths of these innocent unarmed people. If anything it created an environment where the law is respected less.
I mostly agree with this, but there needs to be an effort to hold people accountable when mistakes are made, and to change processes to help ensure that these mistakes don't happen again, or at least happen less often. Police departments across the US seem near-violently resistant to this.
I also think the existing criminal courts and prosecutors hold police reasonably accountable. They could do better.
edit: misread the title, assumed this was about them doing this in Paris (also recently announced)