There are two Gabriels in this story, but the purpose of the father and son sharing a name actually has literary significance for how one interprets the plot.
Consider that perhaps they are both named Gabriel because the father is a metaphor somehow. In other words, the father in this story can be seen to represent the parts of Gabriel that he doesn't like about himself, and then the story takes on another meaning.
Instead of condemning his father, he finally answers the riddle of shame. Shame is the voice of his father criticizing him unfairly. In his daily life, it is literally his father's poor review of his book that bothers him most. But his father's character is shaped by cowardice, secrecy, and even betrayal of the public. Therefore, he is not a fair judge of character, because he is shaped by his own guilt and shame.
But that doesn't mean the son isn't vulnerable to his father's opinions. There is simply nothing a child can do to stop feeling attached to the criticism of the father—except that when the father is brought into the public for the traitor that he was, then Gabriel can be free.
