@SpookyFBI
I don't think that you are going to like this answer, but to me the difference between teaching children about homosexuality and being trans is this.
In being trans, there is no point at which you can actually be what you say you want to be, biologically speaking. Actually being homosexual is easy, you just have to say you want to have sex with members of the same sex and live your life that way, done. Being trans means a form of continued permanent dissonance - this might be the best way for someone to live and they might alter their body to get as close as possible to how they want to be, but it is not the same as actually having a natal sex body. Therefore, on some level, when you are trans you have to acknowledge and accept this difference because otherwise you are living in delusion. Reproductive capacity is an obvious one that can't be changed, but also, if you are a trans man, the best penis they can make you is not going to get erect without being pumped, or if you are a trans woman you are never going to have periods, have a genuine menopause, have a vagina with a functioning clitoris (and you may have a vagina that you need to dilate several times a day, or if you are a child on puberty blockers you may not have sufficient penile tissue so they may have to make a vagina from your bowel, which may smell). Other people may prefer not to date someone that they don't understand to be fully the sex they are attracted to, or cannot even hope to have children with. If you don't pass well, you will be aware that others do not see you as your preferred sex, or you may have to spent vast amounts of energy trying to pass as well as you can. You may need to acknowledge your biological sex in getting appropriate healthcare. None of these points are intended to be hateful to trans people and many trans people will find a way of living that accommodates the difference well, but the differences are facts. It is not possible to fully change sex - it's an approximation.
As such, it is not reasonable to present this pathway to children as something that is anything other than a compromise, because it is otherwise not possible to give informed consent to a pathway (which includes affirmation, which makes it very hard to announce that the identity you shouted really loudly about just isn't you any more and frequently leads to transition in kids who might not otherwise - the Cass review spells this out) without understanding all the facts.
Adult trans people don't want trans to be presented as a "least worst" or compromise option, because it sounds unfun and disempowering and disrespectful of trans people, but truthfully that is what it should be presented to children as, because anything other than that is dishonest and cannot form the basis of informed consent, because there are disadvantages in changing your body and there are also disadvantages involved in identifying as a sex other than your natal sex because there will be experiences that are talked about by others of your desired sex and not open to you.
Children need to be told that it is difficult being trans, because it is impossible for it to be anything more than a compromise, but that trans people should be respected and valued for finding a way to live their lives that is best for them. Instead, they are told fairy tales about what is possible and then told that if they are trans people might hate them, which just creates a sense of struggle that is very attractive to the teenage brain that is still trying to distance itself from being a child and trying to find independence of its parents.
I don't hate trans people. I would be deeply concerned for my child if they decided that they were trans because the messaging really encourages them to believe that anything that isn't possible for them is as a result of prejudice and this really isn't a healthy place to be. I would also worry hugely about the medical side of things, for the reasons @BonfireLady suggests, but I would love them and try to muddle through nonetheless.