One individual is not 'empirical evidence.'
So we don't dig up a bunch of bones and look for evidence that dinosaurs evolved into birds, we predict that if we dig, we will find something that looks a little like a dinosaur and a little like a bird, and then we dig.
Reflexive ideological dismissals, on the other hand, are just tedious.
Exceptions if people's self-conceptions are what is actually being studied; in that case collecting self-reports can be legitimate data-collection.