Deafness is an impaired function. The medical arts are properly used to restore normal function; heal injury; cure disease.
In the case under discussion, medical techniques are bring used to impair normal functions, namely growth and maturation: not as a side-effect, but as the intended result. That is not ethical. It is the opposite of the purpose of medicine, which is to achieve health and healing.
In short, there's all the difference in the world between repairing abnormality, and deliberately pursuing abnormality.
Then I hope you're against all cosmetic plastic surgery, Botox, teeth whitening, etc. etc. etc. all those things that medicine does to create things that are not found in nature -- abnormally white teeth, abnormally perky boobs, and abnormally unlined foreheads. Medicine does those things too.
We're talking about keeping someone SHORT for gosh's sakes, we're not talking about creating Frankenstein's monster. Tall or medically kept short -- what does it matter? Constant love and attention v. crapshoot - that matters in the grand scheme of things.