Because the obvious answer is that no, there were not a rash of suicides by trans kids in the era of zero acceptance of kids being medically and surgically altered for purposes of "affirming" their gender, even though there was no "Trans Hotline."
Gender Dysphoria is strongly correlated with depression, so people experiencing it may have committed suicide. But they would have needed a depression hotline, or a general suicide hotline.
You don't help a person with body dysmorphia by telling them that
Yes, your body is wrong, wrong, WRONG. You problems can only be solved by changing your body. If you, at 105 pounds, identify as far too fat, morbidly obese, in fact, then you are too fat. Spend more time in the sauna and eat only lettuce and cottage cheese until your body affirms your vision for it.
Do you understand that that would be the wrong thing to say on a body dysmorphia hotline? Can you explain why? Try to put it into words, just in your mind.
Then - plug in Gender dysphoria for Body Dysmorphia and hormones and surgery for diet and sauna, and you may come to a better conclusion than you have come to by listening to left-wing media.