What if Hamlet is actually a meta-play about tragedies, with Hamlet trying to reshape his reality into a tragedy, as he is so fond of tragedies? If one interprets it in this way, when Hamlet finally talks to Fortinbras, the meta-tragedy interpretation of it would be that Hamlet realizes that Fortinbras is the real hero of this story. Fortinbras is going through the exact same experiences that Hamlet is, only in Norway rather than in Denmark. His father was also killed, and he is seeking revenge on his father’s killer and trying to reclaim lands that were stolen from him, and he also has an uncle that has risen to the throne over him. What Hamlet realizes in his mind is that he is a character in Fortinbras’ story, and the tragedy is that he is not meant to survive this, because the real story is about Fortinbras rising from the ashes and becoming the true hero that is needed.
There are comments about how Hamlet and Claudius have very similar personalities; they both are defined by not being perceived in the traditional masculine sense of this time period. Hamlet is just a scholar, and Claudius comes off as a career politician. When Hamlet realizes then that Fortinbras is the real hero of this story and that it is his job to make sure that Fortinbras becomes the hero of the story, his tragedy is that what he wants more than anything in the world is to experience the revenge play but he realizes that he is not the hero of the revenge play. Revenge plays were so important to him because at this time they were probably the most popular type of entertainment in England. So this is why Hamlet has to kill all these people - because he realizes that this is not really his story; rather his story is just to facilitate Fortinbras to rise to be king. Hamlet’s idea is that Fortinbras is the one who truly deserves these honors, not him, and as a good student of theater he is going to make sure to accomplish that. He thus does not feel any guilt when he disposes of people, as he feels that he is doing what he is supposed to do.