Relativists and Universal Human Rights
Relativists cannot consistently make charges of unfairness or injustice or try to promote any kind of universal human rights. Under relativism, the notions of fairness and justice are simply incoherent since both ideas declare that people should receive equal treatment based on an arbitrary external standard.
An example would be relativists in the USA trying to stop so-called female circumcision in Muslim countries. You cannot consistently maintain you are a relativist and at the same time try to promote arbitrary rights for people who believe differently. Either it is objectively wrong or you are imposing your own arbitrary morality.