I feel the owner's should retain the name of the restaurant. It is not glorifying Hitler or humilitating the Jews. This name should remind us that Sovereign God is in control and when His people fail or go against the principles laid by Him, then He raises people like Hitler for correction. Even today this principle works. Who divided India into Pakistan and India? Now the terrorism has reached even to them who divided the country. For every wrong action of man there is consequence following it. Though we may like to forget many names in the history, remember, they were allowed by a Sovereign God for a purpose and He removed them after their work was over. After all life is a Universal theatre with God as Director. At least to me this is what I am reminded off whenever I pass the reaturant.