Why categorize anything at all or even have adjectives? The point is that we categorize things for the sake of clarity. I’m or course not mad about miscategorization, but it can have an impact on understanding. Something isn’t true just by saying it.
The case of gender identity isn’t a matter of letting them be what they want to be; it is letting them be what the are.
Of course nothing is really happening here, but even if it were, it would be fine to complain about people identifying as something absurd. Those people are usually mocking gender non-conformity so fuck that.