Defining the picture

How would you respond to this if you were there at the time?
(how did they hire them in the first place?)
I feel very offended right now.I am also puzzled.I personally don't even know what this means but I'm guessing that they're referring African-Americans to monkeys.They are also referring Africans as retards and that Africans don't have common sense.
That's all I could get from the picture.