The thing is, there are other facts in this case that are not in the above piece. You know, the rest of the story. Some of them bode well for the truck driver, some do not. It'll be up to a grand jury as to which facts to consider. Justice, sweet or otherwise, is the administering of a deserved punishment (or reward). Many people oftentimes confuse "justice" with "revenge", thinking that, or quite literally, justifying their revenge as being a proper administering a deserved punishment.
There have been several truck break-ins in that area recently. Five on that lot alone where that truck was parked, a motor carrier's private property. Did the driver vent his frustrations over the recent break-ins, where the perpetrators got away, onto the burglars that day? If so, does that do him more harm, or will a grand jury accept that as a mitigating factor in an understandable reaction? The dead guy was 60 years old. How old was the truck driver? If he was in his prime, 20s or 30s, that might no go over well with a grand jury. It's a fact we don't know.
I don't do wasps very well. I've been stung and I don't ever want to be again. When one is near me and I feel threatened, which is whenever one is near me, I kill it whenever I can. And I don't just kill it, I want it to be so dead that there is no question that it cannot somehow harm me. In a concentrated fit of rage for survival I'll beat, smash and crush it to a stain. I have a feeling that I'd so the same thing to someone who attacked me with a pipe or some other weapon. I'd keep beating until I was absolutely sure there was no chance that he could come back and harm me, even if it meant killing him. I don't think I'd dance with glee afterwards, though, and I certainly wouldn't expect others to be giddy over the loss of life. The driver was probably justified in what he did, but I don't think I'll put on a party hat over it.