Define justice, and explain on whose side should "justice" fall?
I'm sure many more articulate than me have done that if you don't know. Justice always falls on the side of the oppressed.
I honestly feel bad that the man was murdered. I cannot find one reason to justify what was done to him. But on the other hand, he does not deserve to be a martyr. He was in a high profile, dangeroud profession, and he knew the risks.
By your reasoning Audie Murphy was just an ordinary grunt.
And he wasn't killed by a "terrorist", he was killed by a long time whackjob who actively engaged in attention seeking behaviors. Despite CNN only quoting two extreme fringe groups praising his death, the mainstream, credible pro life groups are condemning this.
A terrorist is a political soldier of fortune committed to a cause and willing to kill innocent folks to make political points. This is exactly what the assassin was. Perhaps you can define what you see are "credible" pro life groups and extreme fringe groups. That seems two names for the same thing.