The false premise goes something like this: Christianity, as a historical social phenomenon, basically adjusts its moral doctrines depending on the prevailing social conditions. Christianity, after all, gets its doctrines from “the Bible,” a self-contradictory grab-bag of miscellany. When some readings from the Bible fall into social disfavor, Christianity adjusts them accordingly. There are verses in the Bible that condemn homosexuality, but there are also verses that condemn wearing clothes made of two threads, and verses that allow slavery. Christians today find ways to lawyer their way out of those. Therefore, the implicit argument seems to go, if you just bully Christianity enough, it will find a way to change its view of homosexuality, and all will be well. After all, except for a few shut-ins in the Vatican, most Christians today are fine with sexual revolution innovations such as contraception and easy divorce.
Look, there’s obviously some truth in all that. Not every single bit of Christian morality has held constant over a history that spans two millennia, every continent, and almost every culture. And as Christians will be the first to admit, many strands of Christianity have been very accommodating of the idiosyncrasies of its host societies.
But this premise is also fundamentally mistaken, because the history of Christian ethics actually shows that the faith has been surprisingly consistent on the topic of sexuality. Christian opposition to homosexual acts is of a piece with a much broader vision of what it means to be a human being that Christianity will never part with.
We just had a sermon where the theme was that if you are truly a follower of Christ, your heart will be changed and you will desire to be obedient to God and His commands and to live a holy life.