D, at the time the United States was a country of cruelty and selfishness for its own country, helping everyone in the country and letting them be free, but ruling over everyone else which is a reason that America is as economic as it is.
it means that even though a slave can do anything for you, or you may hurt them, it won't give you happiness. it applies to you today because people are still racist and bully people for being black, though it'll give them no happiness.