To judge failure, you would want to know what the cop knew at that point, i.e., what the dispatcher told him. You would also want to know what he was thought about handling terrorists and mass killers. He was probably taught to shout at them, be very strict, tell them they are likely be shot of they don’t obey. Don’t give them a chance to pull a gun.
We tend to want to judge with the benefit of hindsight—info that the cop did not have—he was not a terrorist or mass shooter, only had an air gun to shoot birds, did not have a hand gun.
		
		
	 
There is also equivocation to consider.  
Your caveats all predispose a jury to find no fault in the killing officer when it is obvious to the citizenry that there is plenty of fault.  The presumptions of the dispatcher, the overreactions of the officer, the manner in which the officer's animus created and exacerbated terror in the victim, the ratcheting of tension by the officer until he rendered the victim near hysterical, all are accountable actions and not excuses for the slaughter of a citizen as we so painfully observed.  However, the criminal trial bias is, as has been clearly stated and as evidenced by the officer's acquittal, is all for the cops under the absurd bias that the difficulty of their role gives them extreme protection in prosecution.  However, the ire of this citizenry is growing, and it is but a matter of time until legislation will pass in the coming years to reverse this travesty.
The excuses of whatever the cop was thinking could just as easily be mirrored defenses for what any psycho misconceiving threat around him and acting out violently and killing.  To be sure, juries mitigate punishment with institutionalization when such paranoia is a clinical condition rather than mere hatred and hysteria, but even then they lock up the killer. 
The fact that civil litigation often re-institutes blame on both the cop and the authorizing police force should be a clear indication that we are institutionally allowing police to have impunity in exchange for money given families.  It is quite literally blood money being paid out to "excuse" the cop from time in prison, a probable death sentence. 
	
		
	
	
		
		
			Death penalty is a monstrosity and I'm evidently against it. And once again, revenge is not justice. Killing the cop would have no effect by the way. Much better to improve the education and training of the police men.
		
		
	 
My friend, although I respect you and the views of pro-lifers in the death penalty debate, the definition of justice is indeed revenge.  Google readily defines revenge as 
	
	
		
		
			1. the action of inflicting hurt or harm on someone for an injury or wrong suffered at their hands.
		
		
	 
All judicial penalty is 
exactly that, with the State acting as proxy for the empowering constituency of that society.  Park illegally, and the State imposes a fine, impounds a vehicle, and the perpetrator is "harmed" in return for harming society and his fellow citizens.  Rob a market, steal a car, defraud investors, and the State harms you by fines and imprisonment for the harm you have executed on the society.  Rape someone, kidnap, murder, and the State takes extreme action, namely life imprisonment or execution, on behalf of the harmed.  It is a monstrous penalty to be sure, for a monstrous crime.
We disagree on the cop's death (by the State, 
not vendetta by a citizen.  It might not stop the family's mourning, nor restore the missing man to his family, nor even make the world "better," by most reckoning, but it would satisfy the blood spilled by the taking of blood.  It is an ancient code, and whether some societies now eschew it or not, there are plenty who disagree, even within those pacifist societies today.  For many a survivor, life can go on with more healing than with the killer still alive and breathing the very air the victim is deprived of today.
And, many would and do argue that a cop facing the death penalty for such an act would absolutely have effect on how the system protects and sanctions rogues like the officer guilty of the Mesa killing.  It would spur the very education and training the police forces use.  Even that statement presupposes his training was somehow deficient rather than him being a hate-filled man looking for a sanctioned role in society to enable that hatred. 
What is more likely is that the training was correct for SWAT situations, but the counterbalancing critical judgment and discernment was not used.  The arresting officer always has the onus to assess and re-evaluate as conditions unfold.  This video showed the opposite.  The victim was the Enemy of the People and was regarded as such no matter what evidence was obvious to the contrary.  
That attitude is exactly what the citizens object to.  What will cost the People dearly in civil court settlement is the failure of the entire team to use their brains instead of their testosterone-filled, penis-proxies, a.k.a., their fully automatic weaponry.
	
		
	
	
		
		
			I don't understand why Ana Kasparian the Young Turks host and average people from youtube can watch the videos and JUB members cannot.  Are we so precious and delicate and cannot watch real stories (with warning)?  I do understand if youtube the company don't want their videos to be shown on JUB.
I'm sure youtube already removed inappropriate videos like gore and beheadings ... etc.
		
		
	 
You seem to have progressed from your views on "inappropriate" videos, or am I mistakenly remembering you posting the beheading videos in this very forum a few years back?
To understand why 
The Young Turks has a different standard on liability than JUB, consider the differences in the two.  TYT is an online television show, or more technically, a podcast.  And, unlike amateur videos uploaded by millions of non-professionals, TYT's show is produced by a professional staff, filmed by actual camera-men, and is more akin to MSN.com in nature. 
As such, it has a large staff, not only of on-screen persona, but also writers, producers, and legal staff.  Being an edgy, confrontational, anger-based medium, they build in the legal liability into their cost of doing business.
Now, compare with JUB.  It isn't a professional broadcast at all.  It not only doesn't have a large staff, there is every indication that it probably has less than ten employees, and relies on volunteers for our dear forum here.  The income brought in by the porn is probably less than 1/100th of what TYT's earns, with no actual legal staff or intent to ever go to court with any issue, unlike TYT's means.  
Therefore, it is likely the legal liability drives JUB's caution, not mere sensibility to gore or even hate speech.  Then again, it is a porn site, so why would the owner(s) allow or encourage anything so off topic?