*
You are confusing a bunch of different concepts. One of which is the difference between "mere possession" (properly holstered), as to which you are correct, and the act of having it in one's hand, or actually trying to get it there, when ordered to stop. Decades of research (including reviews of the deaths of cops) shows that the first indication of actual resistance is not complying with that lawful direction. (Immediate compliance is not optional - it is mandatory under the Constitutional analysis and every state statute I've ever seen.) I've dealt with armed people - didn't care much. We always assume everyone is armed with something anyway. It's the movement toward putting that weapon in action that makes the difference, and that is what was happening here.
Accidental/negligent shootings are not the same as shootings with which the average person disagrees. A MAJOR problem of the last few years is utterly unqualified persons, usually with an agenda not consistent with the actual law, and based on irrelevant and dishonest criteria, have opined loudly, and their mindless bleating has been recklessly parroted by the mass media. As such, a lot of misinformation and disinformation is accepted as correct by people who have never been provided the correct information. Among that is that cops kill too many people - this is a deliberate falsehood. Anyone who researches the number of assaults on officers that would justify the use of deadly force and then compares that to the number people cops kill will find that AT MOST, American LE kills 5% of those offenders it could and by necessary implication should. And, with the examples I provided earlier and others - there have been more frivolous/malicious prosecutions of officers in the last few years than there have been unlawful shootings. What we need to see more of is officers disciplined (retrained or fired) for putting others at risk by not firing.
There is ample research and literature, that makes it utterly clear that self-defense is in fact preemptive. I quoted this in a recent amicus brief* to SCOTUS
https://www.supremecourt.gov/DocketP...026%202018.pdf: "The best use of justified deadly force is preemptive. That means that it is timely enough, and effective enough, to prevent an
imminent risk of serious injury (about to happen) from becoming a
definite attempt to cause serious bodily injury (in fact happening)." Urey W. Patrick and John C. Hall, “In Defense of Self and Others -- issues, facts & fallacies: The realities of law enforcement's use of deadly force”, p. 100, (3rd edition, 2017) (emphasis in original). This decision must also reflect that pistol rounds suck as a rule - the myth of the one shot stop is just that. In reality, it is more like a 4-7 shot stop, maybe, and that must also reflect that time to realize the that the shots have had their desired effect is part of the calculation (a couple of seconds). There are at most 1000 lawyers in the US, and probably closer to 500, who are actually qualified to opine on the issue. The litigation quality is often abysmal.
*(Dave and I wrote the brief; John filed it for us; I am one of the named amici in my corporate name; the other is my co-author.)
I have seen far too many LE command officers who are clueless and afraid when it comes to use of force; they don't want their people well trained because they might actually do things correctly and kill an offender, and while I don't have time to look for it now, there is actually a report in which a Chief said he would rather go to an officer's funeral than deal with a justified OIS. That view is not an outlier - it is common.
I understand the existence of emotional responses to uses of force. Force is ugly. Effective force is really ugly. That does not make it wrong.