it's a good example in the sense that it is a perfect example of gender affirming surgery.

not good as in the procedure is good, but as in a good fit for gender affirming

I'm going to directly compare this to top surgery or bottom surgery in trans people because i believe those are the best examples of gender affirming care but this also applies to hrt. I'm not trans and im not a pysc so take this with a grain of salt.

These men dont feel Dysphoria over their height what they are feeling is Body Dysmorphia. Body dysmophia is obsessive-compulsive disorder over a body part being 'wrong' or defective. An extra inch or two of height is not associated with being male. They will still be recognized as male before and after. They feel like they are male both before and after the surgery and gender never comes into the equation. They are obessing over height because of a mental health condition causing them to hyper fixate on this 'issue' that might not even be real. There are men who are like 6'1 getting height surgery.

Now if we look at top surgery for a comparison. Gender Dysphoria is described as an psychological distress where they identify with a gender other than the biological gender they were assigned at birth. FTM trans men might feel dysphoria from having breasts and top surgery directly addresses the root cause of the dysphoria. Breasts are a primary sex characteristic so this makes sense, something like botox would not be considered gender affirming care I believe.

It gets blurred because a lot of trans people also suffer from body dysomorphia and hyper fixate on body parts but there seems to be a clear distinction between the two conditions and height lengthening surgery doesn't fit the criteria for gender affirming care.