The judge makes a point of stating that he'd give Gerry the death penalty for treason if Gerry had been so accused.
What is the meaning of judge's statement?
Gerry and the others were accused of various crimes that did not include treason. They were found guilty and given lengthy sentences. In other words, they will be in prison for a long time, if not their entire lives. So the judge's statement implies that something like
You're lucky you weren't accused with treason, or else I would have sentenced you to death!
Or at the very least, he is implying that Gerry deserves to be sentenced to death for his crimes.