What is the significance of entering the Pichot house through the back door? What other signs of racism are there?

When Grant went away to college he vowed to never enter through the servant's entrance of the Pichot home again. The significance of entering through the back door illustrates how things haven't changed. His education was supposed to free him from his past, and yet, when he returns home, so do his submissive behaviors. He is sickened by where he lives, repulsed by the way his family is treated (and acts) , but he also finds himself following that same pattern. He goes through the back door like an inferior, lowers his eyes in submission, and treats Pichot with the respect he is denied. His actions represent the many ways in which the world has changed, all while staying the same.