Oh, I agree with you completely that detransitioning is the absolute worst-case scenario and is to be avoided at all costs. That must have been an awful experience for the people you know.
There will always be some people who transition and then regret it. That's just a fact of life and we should not try to dismiss or minimize it. I also agree with Reine's point that TSes who make glib statements to CDers that they're probably going to transition are irresponsible.
I think our only point of disagreement is that I think it's OK to point out the reality that some TSes start out seeming to be CDers and only later realize they're TS. I do not think hiding truthful information helps anyone, so long as we disseminate the information in a responsible way with lots of qualifiers saying the numbers are unknown and likely quite small.