Hamlet is referring to Polonius when he says "These tedious old fools".
In Shakespeare's play Hamlet, Polonius is the counsellor of the king but he is also Ophelia's father. He is on Claudius's side and he even commits to spy on Hamlet. Moreover, throughout the play, Polonius tries to control her daughter's life. He is the one that tells her to stop seeing Hamlet. For all these reasons, Hamlet considers him a "tedious old fool". Later in the play, he kills Polonius accidentally.
