Milkman in Song of Solomon is the third Macon Dead, with the name originating because of a slip up. We learn later that the real name of Milkman's grandfather was Jake, but perhaps the better name for him and his descendants was Macon Dead, many of the reasons for which refer the the name sounding like "making dead".
Jake was born a slave who became free and, because of his freedom, was able to own a farm that was amazingly successful at growing peaches for its location. It could be said that he started a new life when his name was changed to Macon Dead, so the old life and name of Jake were metaphorically made dead. He was also killed, or made dead, for his land.
Macon Dead II more directly fitted the name "making dead". After his father was killed, he spent a night in a cave, where he stabbed a man to death. He also wanted to kill his wife after he saw her in bed with her father, and he tried to kill Milkman before he was born.
Milkman was rarely referred to as Macon, and his father, from whom the lineage of Macon Dead came, had nothing to do with the name "Milkman". He also tried subtly to distance himself from his father, and, therefore, the meaning of his name. As such, it makes sense that Milkman didn't do much killing or getting killed at first. Even as Hagar tried to kill him, she always failed. Only as he got to learn and care about his family's history did his given name meant what it sounded like: Hagar died because of him, and (I think) he made himself dead at the very end of the book.
Even the Dead who was barely known as Macon ended up embodying the name that his grandfather was accidentally given. If the name Jake were passed down to Milkman and his father, the name wouldn't be nearly as descriptive of their lives.
