If you’re using Marissa Alexander to demonstrate your point, you either don’t understand the laws governing use-of-force, or you don’t understand her case. Or both. Her case was similar to that of Jerome Ersland. Both used lethal force well after the justifying threat had ended. That’s not self-defense. That’s murder. Like many of the people in this thread, neither Alexander nor Ersland properly understood the laws governing use-of-force.
I haven’t reviewed the Brittany Smith case, but I suspect I’ll find a similar problem.
Your citizenry’s permissiveness in wild west style police justice
I reject your characterization of defensive force as “police justice”. You can certainly find cases where police have used excessive force, such as Breonna Taylor, Philando Castile, George Floyd. But these cases are the rare exception, and our citizenry is certainly not “permissive” of them.
The process of “justice” starts when the accused submits to the authority of the courts. Fleeing from the court’s jurisdiction invites the use of force; using deadly force in an attempt to flee endangers lives and thus invites a lethal response.