I think you're confusing "sex" with "gender".Depends on the science. They typically believe in genetic science while the libs believe a human can pick their gender. What's the difference? One science can be used to collect taxes and the other can't?
No one disputes the science of sex. Some people do choose a different gender, however, because gender is behavioral/cultural, not physiological.
And nothing with how someone identifies makes them liberal or conservative, although all the hate from the right does pidgeonhole a lot of LGBTQ people into voting liberal.