Back in the 00s, the anti-LGBT culture war targeted primarily gay people, and it primarily used religious arguments. The Bible condemns homosexuality, marriage is a sacred institution, it's a violation of Christians' rights to make their churches marry gay people, &c.

Clearly, it didn't work. During the 10s, when gay marriage was legalized, conservatives were dealt a pretty decisive blow on their anti-gay agenda, and so they shifted from targeting the LGB to targeting the T (they always targeted trans people, of course, but they really ramped it up during the 10s). With this change in focus came a shift in rhetoric. The right-wing certainly does argue for oppressing trans people on religious grounds, but you're a lot more likely to hear them use scientific-sounding justifications. They'll talk about chromosomes, about anatomy, about how "biologically there are only two genders," about "people trying to put their feelings above objective reality." They'll throw around words like "rational" and "reason." This of course ignores all kinds of actual science, such as the degree to which gender is culturally constructed, the existence of intersex people, how gender affirming care is the only dysphoria treatment shown to be effective, and a thousand other things. It's anti-scientific to its core, but it can fool a casual observer into thinking it's scientific if it's telling them what they want to hear. It's a bigotry for a materialist age, palatable to bazinga brains and nu-atheist Redditors, and maybe it's just anecdotal, but it seems to me to have more traction among a younger, hipper crowd than the religious arguments ever did.

I can't help but wonder if this pivot was concocted in some right-wing think tank somewhere.