Can a person transition for the wrong reason?
For the record, the reason people hate this epsiode so much is that the answer to this is, well,
no. For someone who wants to transition, they should be able to, because the vast, vast majority of cases in which transition is a bad idea are ones not where the person seeking care are cis.
Nobody transitions in order to grift. People who actually believe this is a regularly occurring case are promoting a view of trans society that even people presenting strawman versions of identity politics
(and it's not that you don't see them, ELECT * MORE * WOMEN * FACISTS takes definitely exist in the wild a la the coup deposing Evo Morales) would say are completely false and do not hold up under scrutiny. If being transgender were a free paycheck, then nobody I know would be struggling as badly as they are.
The thing about being trans is that at the end of the day you have to assume someone who says they want to transition wants to transition, that someone who says they are a woman is a woman, and this is
especially because these definitions are broad and cannot be verified from external knowledge beyond, say, someone being happier on hormones than not, because gender identity is a personal, internal thing. Hell, even if a notorious cheap hack grifter like Charlie Kirk, professional ADBF, decided one day that he would transition to prove something about trans dishonesty or how it's not really that hard being trans, I would assume that he knows enough about what he actually wants that I my first reaction would be that he was trying to redirect transphobic attacks but is legitimately, despite his claim, attempting to better live out the life the way he is most comfortable.
I once asked a trans friend about something related to this -- would it be worth intentionally misgendering the people who are complaining about pronoun-havers on Twitter? Her reaction was clear: of course not, it would mean that transgender identity would be something that we could disrespect as soon as it became politically inconvenient. It's never about just the one case, and it's
certainly never just about the one case that people want to misrepresent and point and laugh at.
Again, the only people for whom transition is not justified are cis people; not seeking transition is something of a definition here. That is, people who do not need or want transition should not receive it, and anyone else should. If the point of the show is to suggest the athlete here had no need to transition, should not have transitioned, does not feel more human and fulfilled as a result of undergoing transition...then they have made an episode about trans issues that does not have a single trans character in it. Instead of centering issues that trans people experience, they center issues that transphobes lie about.
Having the focus of your show in 2019 not be actual transgender people but transphobic straw arguments, is bad.