So we should call that sex dysphoria, gender would be a misnomer here (see above). And that may be the case, but it is hard to imagine that it is innate as transgender (another misnomer) proponents claim. And even if it is, it's hard to say that a surgery is the right solution. As you say it is like the leg amputee, clearly that is not the right course of action. Same with plastic surgery and steroids. But even there at least there one can say they now are strong or pretty (still debateable) but what can a male that removes his genitals say? I am female? Clearly not. I am a woman? A "woman" gender taken as the emotional state of a female is already a problematic idea, as I explained above. So we are left with nothing.
All this to say that feeling that you want to remove your genitals should not imply that you want to wear a dress. If it does then we must say that there is some innate difference between men and women beyond sex. Especially if we describe the "woman" social construct to be the result of a domestication process. If this were true, feeling that you are a woman would certainly not imply any domestication, as the person was raised as a man.
The last atempt would be to say that wanting to be a woman is a second order effect of sex dysphoria (in a male) caused by society. But then we have already given up on him being a woman to now wanting to be a woman as a sscond order effect of sex dysphoria. And it is of course counter to the claim that the surgery is gender conforming, as the surgery first order (ie. sex dysphoria) and gender is second order. Rather the gender change is sex conforming in this line of thought.
Now I agree that more research needs to be done on sex dysphoria, but unfortunately I don't think any unapproved conclusion will be allowed to be published or if it is we be labled transphibic and ignored.