That isn't entirely true. Transitioning is very recent idea. Being trans and transitioning is also intimately tied to pharma capital complex.
There were many ways of being queer and trans which have been erased over time. Simply consider the native American stuff and also Indian motions of hijra.
The point is that these new ideas pretend that they are all neutral and they have arrived at the truth. In the process the constitue their own subjects who are interpellated in these frames. The people who believe and fall for this new discourses are produced by these new technological and scientific advances. It isn't a truth waiting to be grasped out there.
The point is that alternative routes of making meaning of these phenonemon have been erased and other alternative pathways are blocked by suggesting that this is it.
Alienated not only from the products of our labour, but increasingly the original tool of our labour; that is, our bodies. That's the likely cause of the ideological cart overtaking the materialist horse when it comes to gender. At least, in my opinion.
There is no analogical reasoning between germ theory and psychiatry. Psychiatry chooses to individualize a problem in however coded manners at the expense of the social. I am honestly quite astounded by the response that transitioning is the only way to be trans nowadays. This echoes the overall codification of queer behaviour the world over where the normative western queer body language now dominated. If you don't behave or are like them you are not queer.