These washtowel articles are, as usual, rubbish. Changing one's sex is a major procedure, and not one that is to be taken lightly. You will be irreversibly changed--no going back. You forfeit your ability to have children in the traditional sense. You will be on medication--sex hormones--for life. There are risks associated with this major operation. And, to boot, there is as good a chance that it will not solve the underlying problem.
That said, if an adult understands these risks and that it might not even solve the problem and still wants to go through with it, I see no problem with it. They understand that such a change is much more radical than homosexuality--which can be reversed at will if the person goes straight or bisexual later. But, either way, the person should not be guilted into it. Nothing is worse than taking mere homosexuality, which carries relatively little risk and is potentially reversible, and guilting such person into a sex change operation with all its irreversibility, major consequences, and that it still might not solve the underlying problem.
And those washtowels are full of rubbish. Since when is someone that has had a sex change operation supposed to refrain from sex? To me, that is pure rubbish. Taking the stigma out of volitional homosexuality practiced by willing adults would solve that problem--that way, the person would be able to enjoy sex either with people of their old opposite sex, the new opposite sex, or both without added shame and guilt.
This is all regardless of that, technically, you don't change a person's sex. That is determined at conception--if you have a XX chromosome, you are female. If you have a XY chromosome, you are male. Sex change operations, technically, take a XY person and give him feminine traits--even new genitals, but it does not change the XY chromosome. If they would only leave the damn shame and guilt out of it, that would solve the problem as it would not matter whether a person is XX or XY--or some other abnormal combination like triple X or XXY or even XYY.