https://www.revisor.mn.gov/statutes/?id=609.065
I don’t think a reasonable person believes someone unarmed and dying in front of you is a threat of death or great bodily harm(why the jury did what they did) If he believed that, he probably wouldn’t come as close as he had to to deliver a ‘kill shot’ under the chin.
The Minnesota homeowner shot one in the head at point blank range after they were no longer a threat and recorded himself taunting before doing so. (Then he kept the bodies overnight before calling police.)
That more than anything was the clincher on Smith to me. Every state law I’ve read distinguishes between aggressor and defender, with the legal test generally being whether you are in fear of death or bodily harm.
Proximity bears heavily in that, at all times any wise armed defender would want to keep a certain distance (beyond hand-to-hand) and cover between them and the aggressor so as not to negate the advantage of having a gun. When you willfully advance uncovered to point blank range and do what Smith did, you are no longer in fear of your life. In fact you have reversed the roles and are no longer legally covered.