In a totalitarian state, citizens are not entitled to have any opinions of their own. They are not allowed to judge issues by using independent reason and evidence. They are only permitted to have state-approved opinions.
In essence, citizens are supposed to be blank slates. The ruling class will inscribe what you are permitted to say and believe.
A good way of testing loyal citizens is to mandate that they affirm something utterly preposterous. This is nothing they'd believe on their own. To the contrary, this is something they'd disbelieve on their own. So, to test the purity of their allegiance to the unconditional authority of the state, demand that they swear by something ludicrous.
Trangenderism functions as a perfect loyalty oath for totalitarian statists. Pick a fundamental issue. Take manhood and womanhood. Can't get more elemental or elementary than that. It's obvious. It's the basis of human society.
Then negate that fact. Drive a wedge between biological sex and gender identity. Stipulate that gender is either purely psychological or socially constructed. (Seems like mutually exclusive definitions to me.)
Stipulate that gender binaries are arbitrary. People can "naturally" be transgender, pangender, or agenda.
Make that official dogma. Punish anyone who refuses to blindly affirm that dogma.
It's a perfect test of totalitarian statism. You are never entitled to think for yourselves. The ruling class dictates what you are allowed to think, say, and so. And we will insist, by force of law, that you affirm something utterly absurd to demonstrate your unquestioned fidelity as a loyal citizen of the almighty state.