It's easy to simply dismiss Maher here, but honestly people should be taking this for what it is; a new direction in the right's playbook on how to talk about trans issues.
In this case we're moving into a dangerous territory of ascribing being trans to trying to fit into a "fad" and that being trans is akin to likely the same as what people thought being gay was 10-15-20 years ago. That is to say that being trans is something that could be prayed away or something you could just be talked out of being if given the "right guidance."
You may have noticed this trend earlier, but it's becoming more and more prominent that the right is not just attributing being transgender to being a mental illness that requires corrective treatment, but that also a not insignificant portion of people who identify as trans are doing so simply for clout, because I guess the right thinks that being trans is some sort of privileged status?
This is all normalizing stigmatizing transgender individuals and denying them their agency. And HBO promoting this kind of shit should seriously be called out.