Of course, there was discrimination, even there is discrimination today. I like one thing about Islam: its laws were practical at that time. Do you really think Muhammad could have established modern human rights at that time? 

 Good boy, if you believe that the Bible has indeed prophecied Muhammad (here), then you might want to read what this person is supposed to do:  

  13 The LORD will march out like a mighty man, 
        like a warrior he will stir up his zeal; 
        with a shout he will raise the battle cry 
        and will triumph over his enemies. 

  14 "For a long time I have kept silent, 
        I have been quiet and held myself back. 
        But now, like a woman in childbirth, 
        I cry out, I gasp and pant. 

  15 I will lay waste the mountains and hills 
        and dry up all their vegetation; 
        I will turn rivers into islands 
        and dry up the pools. 

  16 I will lead the blind by ways they have not known, 
        along unfamiliar paths I will guide them; 
        I will turn the darkness into light before them 
        and make the rough places smooth. 
        These are the things I will do; 
        I will not forsake them. 

  17 But those who trust in idols, 
        who say to images, 'You are our gods,' 
        will be turned back in utter shame.