There is a big difference between spiritual beliefs and personality. No one can prove whether God exists or not, or what God wants us to do with our lives. An identity experience is a personality trait that exists right here, right now.
Not believing in gender identity is more like not believing someone is an introvert, just because you are an extrovert, and cannot comprehend how a person may enjoy being alone. Extroverts run the gamut from friendly encouragement and invitations to outright bullying via intimidation and shaming, all of which put a burden on the divergent person.
How is a gender divergent going to convince a normie that they can never be normal, and have a right to exist as they are without being tormented with multiple well-intended or malicious makeover campaigns?
Hopefully education and laws will bridge the gap a bit, but this will always be a struggle, because there will always be normals that can't and/or won't look beyond their own noses, and try to put the blame on God. The historical accounts of Jesus have him asking people to love and understand, and it didn't take the church long to warp his message to exclude certain people, and perform horrible things in His name.
We must be constantly vigilant to keep human society humane.