As a nihilist, you can say some pretty radical things about the legitamacy and existence of some things. In fact, nihilism calls us to question and reject the existence of legitimacy. There is no legitimacy in religion, in morality, in government, in authority, nor in liberty. Nothing is legitimate a nothing is moral. No social institution or structure or construct is valid or has any right to exist unless empirically proven too. Life has no intrinsic value, neither does society or the structures of said society. Only what science empirically proves true is true and legitimate, That's what nihilism originally was, after all. it was an outright rejection of authority and morality, and that is what I do today as a nihilist.