Are you willing to abide that standard when the force or threat of force is directed against you or your loved ones rather than against an employee or agent of the government?
You are right, I would react to what I perceive as a threat...then again, you could be reacting to me because you believe that I am a threat. So, where does this leave us, we both believe we are right and need to defend ourselves. All this would need to be sorted out by the cops and courts of course, after the fact...if we both survive the encounter that is.
Kind of like a cop is screwed no matter what he does, right? He sees a kid getting snatched up by a adult and tossed into a car. Is it the kids parent or a pervert. The cop has the luxury of not having to decide one way or the other. QI is there if it was the kids parent and not a perv...his goof is mitigated and the parent is harmed by his goof. If it was a perv, he is a hero.
I do not believe in minor "inconveniences" by the state as the price we must pay for safety. Unfortunately the courts do not hold my opinion as their own.