Kafka wants us to sympathize with the protagonist of the story of couple reasons. The first one is the obvious one and it is that somehow Gregor, who is just an ordinary man, managed to turn into a “monstrous vermin”. The other reason is that as time progresses, Gregor’s family turns on him. They start to treat him less and less like their son and brother and more and more like the vermin that he has transformed into. The passage that I think is especially sympathetic is the part where Gregor’s dad threw the apples at him.
“A weakly thrown apple grazed Gregor’s back but skidded off harmlessly. However, another thrown immediately after that one drove into Gregor’s back really hard. Gregor wanted to drag himself off, as if the unexpected and incredible pain would go away if he changed his position. But he felt as if he was nailed in place and lay stretched out completely confused in all his senses. Only with his final glance did he notice how the door of his room was pulled open and how, right in front of his screaming sister, his mother ran out in her underbodice, for his sister had loosened her clothing in order to give her some freedom to breathe in her fainting spell, and so how his mother then ran up to his father—on the way her loosened petticoats slipping toward the floor one after the other—and how, tripping over them, she hurled herself onto his father and, throwing her arms around him, in complete union with him—but at this moment Gregor’s powers of sight gave way—as her hands reached around his father’s neck and she begged him to spare Gregor’s life. “
This passage makes us sympathize for the protagonist because it shows that his dad has completely turned on him. It is saddening to see that his dad to do such a thing. His mother had to fight his father in order to save him. This is a strong point in the story because it’s an eye opener to see the father commit such a serious offense. It shows how his family is beginning to get sick of him and want to be rid of him. That in itself should make the reader sympathetic for Gregor and the situation that he is in.