Why is Hamlet bothered by the fact that one of actors able to read about death King Priam with such passion?

In the play "Hamlet" by William Shakespeare, Hamlet is not bothered by the fact that one of the actors is able to read about the death of King Priam with passion, but rather by the fact that he himself cannot feel the same level of emotion when contemplating the death of his own father, King Hamlet. Hamlet is struck by the actor's ability to shed genuine tears and display such intense emotion while reciting lines about a fictional character's death, while he struggles to feel anything but numbness and inaction in the face of his father's murder. This contrast highlights Hamlet's internal conflict and his self-reproach for not being able to express his grief and avenge his father's death with the same fervor.