To answer this question the reader need look no further than the first interaction Shakespeare presents between the famous uncle and his even more famous nephew. In Act one, scene two, Claudius declaims the following:
'Tis sweet and commendable in your nature, Hamlet, 290
To give these mourning duties to your father;
But you must know, your father lost a father;
That father lost, lost his, and the survivor bound
In filial obligation for some term
To do obsequious sorrow. But to persever 295
In obstinate condolement is a course
Of impious stubbornness. 'Tis unmanly grief;
In a strange way what Claudius is recommending to his nephew is a kind of generic grief, without being so gauche as to descend into particulars. He’s saying here that all sons have a duty to mourn their dead fathers, no matter how they felt about one another in life. The son grieves publicly almost as a kind of duty tax for the passing of the man who gave him life. Claudius approves heartily of this kind of mourning, but he doesn’t want to go anywhere near the specific, particular, and complex relationship his oh-so sensitive nephew had with his brother, the war-hero, who he has so recently murdered. He knows that if Hamlet can make his grief an abstract thing, the sooner the young man might recover. And the sooner Hamlet recovers from all this moody, sullen, black-wearing grief, the better for Claudius. Even if he had not committed fratricide, Claudius would still be desperately trying to get on with the celebrations of his recent marriage, and his ascent to the throne, and find his footing, now that he’s finally been relieved of his big brother’s, Hamlet senior’s, shadow. The very last thing Claudius feels he needs is some moody boy glooming around the court as a kind of perpetual reminder of how he got the girl (Gertrude) and the throne and all the perks that come with them. He accuses his nephew of being unmanly in his grief, kind of girlish, and by sexist implication, kind of weak.
Later in this same speech Claudius says:
It shows a will most incorrect to heaven,
A heart unfortified, a mind impatient,
An understanding simple and unschool'd; 300
For what we know must be, and is as common
As any the most vulgar thing to sense,
Why should we in our peevish opposition
Take it to heart? Fie! 'tis a fault to heaven,
A fault against the dead, a fault to nature, 305
To reason most absurd, whose common theme
Is death of fathers.
He is saying here that Hamlet is essentially being a silly child, a simpleton and sort of suspiciously atheistic. Claudius implies that if God has a plan for everyone and everything, then to object so strongly to his father’s passing is a backhanded way of spitting in the eye of God, and on His plan. This is incredible hypocrisy coming from Claudius since, for him to actually believe that, would imply that it was God’s plan for him to sneak up on his sleeping brother, out in the garden, and pour a corrosive poison into his ear. The subtext of both these passages is that Hamlet is making a big deal out of nothing since the death of fathers is nothing but a “common theme” to us all. Essentially insisting, both in word and in tone, that since millions of sons have buried their father before Hamlet, and millions will bury theirs afterwards, that Hamlet’s just being a big old baby by acting as if he’s allowed to grieve his own father’s death in his own particular way. Because Claudius is a liar, who lives behind a mask, he cannot imagine that his nephew’s deep pain could be sincere. He has no empathy.
