The "moral" difference was that the traditional salute was seen as a disciplined sign of courtesy inherent to a professional army, and that the hitler salute was considered to be an act demonstrating loyalty to Hitler (or at least, the office that he held). Since the German Army cared more about doing its job professionally than doing silly loyalty things like the SS, the Hitler salute was rarely used until July 1944. After the failed bombing attemp to kill Hitler, the standard military salute was banned, and the use of the Hitler salute mandated.