Whereas he recognizes that he his "offense is rank" and "smells to heaven," he also admits that he will not make amends with God because he refuses to give up what his crime has bought him. He is willing to take the consequences of his actions.
In some ways, Claudius exhibits more heroism than Hamlet. He manipulates fortune and takes what is not rightfully his, but remains unapologetic for his actions; he possesses enough strength to admit that he would do the same again. Hamlet, torn by conscience to smite the morally deficient Claudius, causes the death of six innocent people before he accomplishes his goal. By taking full responsibility for his actions, Claudius mitigates his evil nature.
The mark of a great Shakespearean antagonist is how completely he mirrors the protagonist. Claudius is no more Machiavellian than Hamlet; both ultimately believe that the end justifies the means, and both ultimately sacrifice humanity and humaneness in the acquisition of their goals.
What makes Claudius a villain is that he is wrong, and Hamlet is right. Claudius is a sneak who murdered and lied. Hamlet commits his murders in the open and suffers the pangs of his own conscience. Claudius subverts his conscience and refuses to ask for divine forgiveness. Hamlet seeks contrition and absolves himself of guilt before he dies; Claudius receives no absolution and seeks none. Hamlet will spend eternity in Heaven; Claudius will burn in Hell.
