Hirohito had nothing to do with running the government. He was a figurehead, for the most part. While Japan had an elected parliament, it was dominated by the military leadership (not the royal family).
If you attribute the activities of the Japanese government to him, you would have to give him credit for saving many Jews. Not only did Japan refuse to round up Jews (the Germans asked them to, they refused), they granted asylum to many Jews who reached their territory when fleeing the Germans.