Firstly, you can’t make the whole world agree with you anyway. It’s authoritarian to do so.
So what is trans empiricism? Basically, it’s taking an empirical approach to the phenomenon of trans. To be empirical is simply to be committed to the objective truth, and base our claims on observable evidence. In the empirical approach, observable evidence is taken to be the best representation of the truth. Empiricism is useful because it grounds our thinking in objective reality, and arguably protects us from sophistry.
What may surprise many people is that, the gender criticalists and the postmodernists actually share a fundamental worldview, that is, gender is a social construct created by the patriarchy to oppress women. In turn, this is a particular expression of the general critical theory worldview: that the ideas held to be true by most people are often a social construct to serve the oppressors of society.