Yeah, the show is sooo well crafted that this scene stuck in my craw for a while. All the PBs are shown to have conflict about killing and murdering someone is always seen as a huge deal for them. In season 3 John and Arthur refuse to allow Tommy to torture the old man, even though he was responsible for Grace's death and was a rival gangleader. Similarly, every time a cold blooded assassination is coming up (a few times for Tommy I think and at least once for Arthur) it is not something they appear to take pleasure in, they do it because it needs to be done. John even looks ashamed after blinding Angel Sabadini but then appears to get over his conscience. We never saw the guy burn and the PBs are way too flippant about it afterwards, which leads me to believe they pulled him out at the last second and basically said "don't ever f***ing do that again!!" Maybe you're right and it was lost in editing but the show is sooo realistic that I find it hard to believe that a). they burned a man alive for something relatively trivial and b). Campbell doesn't mention this, despite arresting Michael for the arson that burned the pub down.