Human actions often carry absurdity. I think we should recognise it and accept it, instead of trying to ignore it and hope it will disappear (hint, it won't)
Referring to a sex change as "cutting off their own genitals" is deliberately meant to frame it as absurd or bad compared to more clinical terminology. Your statement is that it is so absurd or bad and yet has some takers ergo any product no matter how bad or undesirable will itself find a market.
This is first of all fundamentally insulting. Second it doesn't make any sense. Those who undertake such surgery aren't choosing between having gender reassignment and a corgi.
Lastly you can't sell shit you don't understand. This is like sales 101.
The absurd part is, of course, the belief that this surgery turns these men into women, or changes their sex from male to female.