If truth doesn't exist, then it's hard to take "relativism" seriously. Aristotle mentioned that it's very difficult to maintain "categorical negations" such as there are no absolutes in morals and ethics. One would have to do much searching, studying, and proving in order to assert such a worldview, and yet the people I find asserting it usually have done little research other than some shallow introspection, and even then it comes across as self-deception.