Well what did you expect to find instead? That they just randomly assigned some people as slaves, that they instated this system throughout the country, without

Well what did you expect to find instead? That they just randomly assigned some people as slaves, that they instated this system throughout the country, without ever thinking about it? Of course there were justifications and theories and established rules etc. Of course these people weren't randomly just evil or stupid - such people do not organize. There is always a system.