Of course, nothing in biology supports anything you just stated. That is merely your opinion, based on your learned biases and fears, which you are of course entitled to.
The fact is hermaphrodites are something like 1 in 100 people, and yet folks just act like they don’t exist, because their existence is “uncomfortable” or “scary” for some. Transgender people are a much smaller number, of course, but just as valid. Why do we fear what we don’t know? Why do we fear what other’s do with their bodies, when it’s none of our business? Who knows?
All I know is whether I “approve” of something or not doesn’t make that thing bad or good, and it certainly doesn’t make someone mentally ill (that’s really absurd, and it’s what people said about gays, interracial marriage, women who didn’t want to marry, etc. before such progress became the norm).
Humans come in all stripes. May I suggest you get used to it.