Regarding below, I remember two years after the Mets-Yankees World Series, when Roger Clemens threw a piece if Mike Piazza's bat at him, the Yankees were going to play the Mets in an interleagues series. Since the series would be played in Shea Statdium, that meant that Clemens would come to bat. Scheduled to start for the Mets: Shawn Estes.
There was all sorts of discussion in the week beforehand that Estes should bean Clemens. But it seemed strange to me that Estes could be moved to attempt bodily harm against someone for an incident that happened 20 months ago when Estes wasn't even on the team.
Predictable enough, Estes's first pitch to Clemens somewhat lamely went behind him. You can read about the incident here.
I think this captures the fear that those wanting to hold onto anger have. If we're not angry when we carry out justice, then we'll be lame when we do it, as Estes was in his attmpt to "bean" Clemens.
But the unasked question is whether the beaning truly was the just punishment for the crime committed.