Yes, but politicians are mostly lawyers too. I think Robespierre mostly sought compromises, no matter his firm principles and no matter what people seem to believe. Only, at the end, he was growing tired and depressed and saw that the Festival of the Supreme Being didn't seem to have the "union-effect" for the deputies that he had hoped. While Saint-Just was willing to compromise, Robespierre was probably refusing because he saw it was pointless, since he knew the others didn't want to.