Right, and therein lays the rub: it's open to interpretation, and things will get interpreted differently by different people in different places and times.
Most medieval Christians believed that transgender people (not how they would have been labeled at that time, but they frequently didn't have a specific word for such people, so we'll make do) were created by God as the gender they identify as BUT were changed by the devil to the opposite gender in the womb. Gender transition was therefore putting things back they way that God intended and was fighting against the devil.
Anti trans Christians today believe it's the other way around.
And this is why evidence based policy making is so important for a successful government.
The acronym was never about sexuality, it was about gender non-conformity. By the same notion, that's what people's attitudes are being measured about: specific forms and sub-groups of gender non-conformity.