The Hulk was always clearly angry..or stupid. And he had a history of avoiding killing, despite all the damage he caused. He also saved people many times.

Red Hulk murdered a SHIELD agent and (most believe) murdered General Ross too. He humiliated beloved heroes. He was working for murderous supervillains. He went on national television and declared he was taking over the country. He did all this knowingly, willingly, and in full possession of his senses.

If Rulk revealed his true identity now? Despite his honorable career, he WOULD be hung for treason.