I assume you are referring to Penelope's request to Phemios not to play songs of the fall of Troy because of her great loss there since Odysseus did not come home from the battle. Telemachus response is somewhat surprising since he has been seen thus far as "shy and diffident" but here is is almost overly aggressive almost to rudeness. He chastises his mother for her request, claiming that it is the Bard's right to play popular songs and that decisions should be made by men. The suitors react to her leaving with an uproar as the men voiced hopes of sleeping with Penelope. Telemachus also remonstrates with them for their inappropriateness, surprising them as well.
The reason for Telemachus' new boldness comes from the suggestions of Pallas Athena who had come to him in disguise. She had urged him to try and get rid of these suitors and had challenged him in a way by saying things would not be like this if Odysseus was here. This is really the first attempt of Telemachus to assert himself and he almost overdoes it.