Starsoul
Truth
I can see your point and its quite a fair one. I can understand if you'd think it could've been more clear. I don't have a clear answer to that, but rather some thoughts addressing possibilities.
For one thing, i think that its reasonable to assume, that the way this same book we're talking about was perceived by people 1400 years ago, is at least, considerably different in some departments than how we perceive it right now. Our perception affects what we see, they were considerably different than us, and i expect their perception to be just so as well.
For a society that already viewed slaves as totally okay. Completely normal and merely a part of the social structure. This might've been then a loud and clear message. People were already threatened by some of the changes that was brought by Islam at the time, and based on my poor knowledge i understand that this was one of the things that made many problems for many people, including accepting the "preposterous" idea that they should be all the same. So like i said this actually might have been a very clear message, to them.
That might have been the case.
Well said. This could probably have been the reason, since all commandments regarding prohibition came in a gradual order, step by step, so that people had the time to think, reflect and mould themselves for the change, absorb the wisdom behind it, see it for its effects, and then move on to complete dis-continuity of the prohibited practise.
Even in case of alcohol, it was asked not to be used while during the prayers ( and before to avoid intoxication) and when people started witnessing the differences of their attitudes, their demeanours and their work being significantly affected under alcohol influence, they themselves were brought to realize that they did awful things when intoxicated. The practise helped them analyze their actions in the light of the divine command and they agreed/accepted it whole heartedly when the final leg of the command was revealed.