I'm going to assume you're asking this question in good faith and, if you are, then the other replies have probably not been adequate explanations.
First and foremost, the Bible does not mention transgender people. It does show that gender and sex are different by, for instance, referring to sexless supernatural beings as male and female, but for the most part it does not delve too deeply into gender at all. To try to extrapolate a position on gender from a text that doesn't really talk about it is sort of nonsensical from the get-go. The Bible no more has a position on trans people than it does on the correct way to make a taco, because it's simply not an issue the Bible addresses at all.
Secondly, the "biological reality" is not "male and female." Biology includes a wide range of people who are intersex. There are people who are born that do not clearly fall into either category, including people who are born with both sets of primary sex characteristics (genitals).
Thirdly, anatomical and chromosomal sex are not the same as gender. Gender is a facet of one's neurology, not one's anatomy or chromosomes. For instance, if someone is born with both sets of genitals but has their male genitalia removed at birth, they are then assigned female by those present and become socialized as female regardless of their biology. They will likely express themselves as female, such as by wearing female clothes. That's gender, not sex.
Fourthly, trans women are often more at risk of being the victims of violence than cis women are. The post has it almost in reverse. Cis women are more of a threat to trans women than trans women are to cis women. In a broader sense, this is also the case when it comes to the rhetoric of the so-called "trans-exclusionary radical feminists" or TERFs who not only spread transphobia but incite people to act on their hatred of trans people.
This is just the first two sentences of this post. It gets worse.
Gender is not subjective. It is objective and there are ways of measuring and testing it. In fact, our modern notions of gender are required to explain certain findings in neurology, psychiatry, anthropology, and social psychology. Gender isn't something that someone can change. In fact, if that were the case, I bet many transgender people would rather be cisgender, but they can no more control their gender than they can control their natural eye color or their anatomical sex. It is just as fixed and rooted in biology.
Autism is not caused by "bad family dynamics." It's genetic. It also doesn't make much sense to say that autism precedes gender dysphoria because, for one, they are separate disorders. Not every trans person is autistic. Secondly, the diagnostic criteria of autism focuses on early childhood, whereas gender dysphoria does not place as much of an emphasis on this, so comparing the data of the two disorders in this way is sort of apples to oranges. Dysphoria could be, and likely is, present from birth, but that's just not a factor in how we evaluate whether someone is suffering from it.
Minors can be diagnosed with gender dysphoria, just as they can be diagnosed with ADHD, depression, anxiety, etc. This is a good thing, because it means that the suffering caused by dysphoria can be addressed in therapy early on. It also reduces the risk of suicide among LGBT youth, which is extremely high due to the social stigma they face and their inability to cope with that on top of the already miserable experience of gender dysphoria. It is not an attack on truth to take someone to therapy when they are struggling with a lack of proper coping strategies; that is plainly ridiculous.
It's secondarily absurd that the complaint about words like "male" and "female" not having any meaning anymore completely ignores the scientifically documented truth of the existence of gender and intersex people. In context, this is basically lying. It's the people who deny the reality of transgender people that are trying to obfuscate the truth.
At the very end, it refers to "transgenderism" as if "transgender" is some sort of ideology rather than a blunt fact about the way some people's brains are. It's like saying "I don't believe in dementiaism" or "I don't believe in sleepism." It's one thing to be ignorant, but it's another thing to weaponize your ignorance against people who are suffering and in need of medical intervention and social support.
This whole post is evil, in the sense that it callously causes needless harm and seems to almost sadistically revel in demonizing and attacking trans people.