They disarmed him before they killed him. The gun is not remotely excusing (or for whatever reason you bring it up).

If he hadn't been armed, this would have been a standard takedown and he would be alive now.

Specifically because he had a gun, the situation became a matter of life and death for everyone involved. Pretti did that, intentionally.

Did the feds, who have been targetted by both violent rhetoric and actual violence in Minneanapolis, react badly? Possibly.

Did Pretti's shitty SIG misfire, leading them to think he was still armed? Possibly.

He's allowed to have a gun, he's allowed to be in public, he's not allowed to interfere with LEOs, and having the gun while doing so brought real world consequences, not legal ones.

Now, Trump will likely try to use this to push gun control, which I oppose, but I see nothing wrong with the situation as it stands. FAFO.