Then let me longcat for you.
These studies examine mental health outcomes for medial transition patients. In the short term, medical intervention is remarkably effective at improving mental states for those involved. Which is viewed as effective treatment. Over time, however, societal pushback, ie disapproval, rejection, targeting, degrades those same mental health outcomes. Which some view as non effective treatment. Because medical transition treats an ndividual, not a society.
Interestingly, this societal disapproval quickly changes to societal support with minimal effort. More information leads to greater acceptance.
To my understanding, filtering out negative mental health outcomes as a result of societal disapproval, is the difference of opinion cited in your truncated link.
Certainly, the Economist is not considering the very low rate of detransition in coming to its lede.