I *think* "indulgents" was the common contemporaneous term for the revolutionaries who didn't want to execute the king. People who actually know about the French Rev should correct me on this if I'm wrong.

"Condemned to learn a trade in order to earn his living" strikes me as coming from someone with a very poetic sense of justice, someone who would appreciate the "I sentence you to yourself" kind of justice. The point is the king is a man like any other and has to live like any other, and if he had the correct attitude then this wouldn't seem like a punishment to him--but since he has the wrong attitude, it's a huge punishment and a huge insult.