Yeah all this. If we had actual hard evidence that chopping your dick off cured depression we'd have no shortage of evidence showing that. Hell if we had actually solid proof that gender transitions absolutely resulted in better outcomes for people in the long term then we'd be having a different as argument entirely. But nobody has produced that to my satisfaction.

It goes against the common sense, there's no medical research inconclusively backing it up. Research is one thing but it doesn't take a genius to realize that maybe someone who wants to chop their dick off is a bit touched in the head and might not be making the most rational decisions for their own happiness?

I mean I guess we can get into the whole thorny argument of, if self harm makes people happier, should we just let them harm themselves? But that ultimately leads us to the suicide problem. If someone is depressed and wants to die should we kill them? (And well I'd say that while death is a "cure" for depression, it's evil, and that we should find ways to help the depression)

Plus we're all going to die eventually anyway it's an inevitability to why rush it?