They haven't understood that young people thinking they're trans has much more in common with anorexia, which is people thinking there's something wrong with their body, which can spread through social contagion.
I think there are parallels with the spread of Bulimia:
'The Strange, Contagious History of Bulimia'
By Lee Daniel Kravetz
(extract)
In 1972, a woman checked into London’s Royal Free Hospital to be treated for anorexia. “I found her symptoms to be unique,” Gerald Russell, the British psychologist who treated her, tells me. “They didn’t match the diagnostic criteria for anorexia at all.” Unlike his emaciated patients with sallow skin and big eyes, Russell’s new patient was of average weight. Her face was full. Her cheeks were pink as the skin of an onion. She was the first of roughly thirty instances of this unusual condition that crossed the threshold of his clinic over the next seven years, each person presenting with perplexing purging behaviors secondary to binge eating. Russell wasn’t dealing with anorexia nervosa, he realized, but something as yet undefined by psychology or medicine.
In fact, he had stumbled upon a condition that science had yet to see in large numbers or identify at any time in the long history of eating disorders. Psychological Medicine published Russell’s ensuing paper on these unusual cases; in it, he described the key features of this novel mental illness he was now referring to as bulimia nervosa. Many in the scientific community objected to Russell’s conclusions, pointing to the limited and problematic sample size he’d used. At the time, however, there were simply too few cases for Russell to draw from. The pool in the 1970s was just too small.
As bulimia gained further diagnostic legitimacy in 1980 with its inclusion in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, Russell ruefully tracked its unexpectedly swift spread across Europe and North America, where it infiltrated college campuses, affecting 15 percent of female students in sororities, all-women dormitories, and female collegiate sports teams. The disease moved through the halls of American high schools, where binging, fasting, diet pill use, and other eating disorder symptoms easily clustered. He chased its dispersion across Egypt, where the number of new cases grew to 400,000. In Canada, it swelled to 600,000. In Russia, 800,000. In India, 6 million. In China, 7 million. In the UK, one out of every one hundred women was now developing the disorder." (continues)
www.thecut.com/article/how-bulimia-became-a-medical-diagnosis.html