What do you mean?
I believe he was replying to post #5 with the opposite analogy.
It is very simple. The doctors should do ABSOLUTELY NOTHING until the kid grows up and figures out what he or she wants to be or if they are happy the way they are. Using a knife or hormones or parents' selfish wishes or guesses, only has and will only lead to disaster.
That you're assuming that genitilia determine gender; but transgenders report that they feel they are actually of the opposite gender. And if they don't know, who does? You and I can't know something like that for them.
So when you say "The idea that you can change a boy into a girl just by mutilating him & giving him some hormones...", from the 'boy's standpoint, you want to leave her with boy parts in the hope she'll change her mind.
Try thinking of a transgendered man as a really homely woman who wants to improve her looks and you may find 'his' actions more comprehensible.