Unlike feelings of sexual attraction which are objectively measurable (pupil dilation, heart rate etc), feelings of having a gender are not measurable. One's gender identity is more like one's religious creed it seems to me.
Some people change religion (or become atheist). Not many but it definitely happens. I am sure we all know a few people who converted from one religion to another, or lost faith, or maybe left their childhood religion then bounced around lots of different faiths, some quite obscure.
Changing religion is big deal to adherents of a faith. There are special negative words like apostate and heretic. Some religions refuse to acknowledge conversion, you are only lapsed not lost.
Adherents to the faith react badly to apostates and heretics, including ones they don't know personally. Odd given that there is no way to objectively know which faith, if any, is true.
Why such negativity then? Often a disciple's life is built around their faith being The Truth. When someone who is in the faith, who understands the faith, decides it is not The Truth, well that can be dreadfully destabilising to the disciples. They may feel anger. They may feel unsafe in their own belief. Others may start to question. All faiths are inherently unprovable which is why they require faith, why they are beliefs not facts. Questioning is dangerous to the religion. There is no guarantee that the questioner will decide that this unprovable faith is the right one for them once they start to think about it.
In some countries it is a serious criminal offence to encourage someone to change religion. A person who does convert will face very serious consequences.
In this country we made a choice to step away from that approach. The bloodshed and burnings weren't what we wanted.
As a person who left a religion (for atheism via another religion first) I feel a tremendous sense of familiarity in how some trans activists talk about conversion and gender identity.
I don't want to see missionaries banned. I don't want to see groups offering introduction to faith for the questioning to be banned. Force and threats: bad. Talking, questioning, thinking: good.