The Chasam Sofer [ליקוטים סי’ י”ד] writes that everybody holds that all דינים such as stealing, withholding wages, fraud etc. are binding on goyim. The point of contention is that the Rambam includes them in גזל while the Ramban learns that they are included in דינים. The Rema [סי’ י] seems to say the same thing.
But it is not pashut. The gemara in Bava Metzia [58b] says that a goy who strikes his friend is not חייב מיתה. The Rambam [Melachim 10-6] that even if he strikes a Jew he is not killed. The Ra”n says that we don’t say מה לי חבל בגופיה מה לי חבל בממוניה – There is no difference between damaging his body and damaging his money [and “damaging” his money is גזל for which he is חייב], otherwise, why would we have an איסור of שפיכות דמים, we could just say that it is גזל?! [See חלקת יואב מהדו”ת י’ י”ד] If so, how can all of the laws of דינים be included in the איסור גזל?! Only גזל includes גזל and nothing else.
Also – how can it be that all of the monetary laws, damages etc. are included in the איסור of גזל and yet the Rambam NEVER-NEVER gives any allusion to that fact. Why keep such critical information a secret??
There are numerous other questions but we will leave it here and hope to continue with the explanation of the Rambam in the near future.