Slaves on the 4th

I believe that Douglass spends so much time argueing points that are common knowledge to everyone because at the time they were still being ignored. People "believed" in the fact that all men were created equal, but for some reason they didn't view slaves that way. His purpose was to inform people that they were being hippocrites, claiming they loved freedom and sitting back as slaves worked for them. It may seem pointless to argue these points, but in reality it was what the people needed to hear.