Well sure, Reinhoehl shot at the Marshals first (according to some witnesses at least) and fled arrest. That is what was reported immediately after the shooting. That's not a summary execution, that's serving a warrant for arrest. That's due process of law.

You are changing the goal posts substantially. Wikipedia defines a summary execution (https://en.wikipedia.org/wiki/Summary_execution) as being accused and then immediately killed without trial. That is not what happened to Reinoehl. He was accused, a judge issued a warrant. He was given the opportunity to come and face justice. He did not. Instead he shot at police. They shot back.

In order for it to have been a summary execution, Reinoehl would have to have been captured and well under the Marshal's control and then killed. Or he would have had to indicate that he surrendered and been shot anyway. That is not what happened.

Ultimately, this situation would have been easily resolvable had Reinoehl turned himself into police, like Kyle Rittenhouse. Sad anyone had to die, most of all Reinoehl's victim, Aaron Danielson, who for some reason (that we all know) is completely ignored in all this.