But it HAS become a fad, and an insult to true trans people, such as those who are intersexed, or have Turners syndrome (X), or Androgen Insensitivity Sydrome (XY female), or XX males, or Kleinfelders Syndrome (XXY), and so on.
People like Rogan and J. K. Rowling are correct to stand against this trend.
In the not too distant past the liberals might have been the first to point to the increase in trans identification as a side-effect of evil greedy corporations polluting the environment.