The shot cop had drawn a gun on someone who was running away.
The judge didn’t even permit the defense to argue “defense of self or others” as a justification.
If it can't, the second amendment is even more pointless than it already appears to be.
I don't think the second amendment is particularly relevant. The point of the second amendment is defense against a tyrannical government so by definition we're in extrajudicial territory and don't care if it's legal or not.
Governments can be locally tyrannical, or tyrannical in-the-moment with the actors immediately involved, but not at all levels or not over a span of time as the pool of people involved grows.
In fact 100% of the cases I know about, of the second amendment's consequences being successfully used against a tyrannical government in the US, it's been a local government that's turned tyrannical (usually very-corrupt local cops and city or county government[s], coupled with a bunch of racism).
(To be clear, though, I'd not personally advance that fact as a strong point in the 2nd's favors as an actually useful-in-practice amendment for the supposed purpose of "defending liberty", as there are at least as many cases of private arms propping up local tyranny, or sowing political terror in the name of tyranny; "a mixed bag" would be a very generous reading of the history, and "net-harmful to the cause of securing liberty" is probably the fairer judgement)
This was shortly before two people got murdered on camera by cops in Minneapolis, and after/around the same time as several other attempted murders (that would have been successfully spun as something chargeable on the victim, if not for video evidence showing plainly that the cops were lying)... so... it doesn't seem like a totally crazy notion to me, that a person might have shown up armed intending only to fire if it looked like a cop was going to shoot someone without a great reason. Maybe a jury would still have convicted (there was a bunch of fuckery with jury selection on this case, incidentally, and I mean way more than usual, even, it's worth reading about; like after what the court selected for on the jury, I believe they almost certainly would still have convicted) but not even being able to raise that defense seems nuts.