I think people are confusing the Buddha with Sañjaya Belaṭṭhaputta who was a skeptic, relativist agnostic existentialist, amoral pluralist in the Buddha's time. His theories of moral relativity, existential relativity, and agnosticism were called "Eel wriggling" by the Buddha and were refuted. Why then do people take the Buddha to be an agnostic, relativist, moral pluralist?
The Buddha did not say that truth did not exist, while he pointed out the failures of the conventions of language. Ideas like 'actions have consequences'; 'behavior founded in greed, hatred and delusion produces misery'; 'becoming less attached we become more creative'; are simply descriptions of the way the world actually works. They give us a basis for a system of values which are not arbitrary. They are truths.
"One is not born a woman, but becomes one."- Simone de Beauvoir