I didn't even know who this guy was until a few hours ago, but holy shit I am glad he got what was coming to him, and I hope the shooter never gets caught and lives a long and prosperous (and most importantly, free) life.
If I was the defense attorney, I think this would be the test case for instructing the jury on jury nullification (which will get you sanctioned at a minimum and probably disbarred if you're the attorney that tries it). I think defendants ought to be entitled to instruct the jury about the possibility. I personally would never disclose that I believe in it during voir dire and also would never vote to convict on some crimes.
Historically it's been used to forgive lynchings, so I'd be concerned that allowing jury instruction on it would cause more harm than good in this political climate.