Once the world convinces you that your worldview (Christianity) cannot account for even the most "basic" of scientific "facts," it's not a big step to then tackle your morality. Or lack thereof.
See, what you fail to understand, as a Christian with a certain understanding of the inherent dignity of human beings, is that human beings at their core are just animals. We're no different than the monkeys (and just look at this weird fossil we found to prove it! No, no, don't offer us any other explanations. We like the one we have). And if we're no different than the monkeys, then you have to understand that we can only really be expected to act like animals.
There's no reason to save sex for marriage. Sex is a biological function that is driven by our passion and desire and besides, it feels good, and since the animals are doing it whenever the urge strikes them, so should we. To save sex for marriage is too restrictive, and it makes us think there's something about it that we're missing in our pure animal instincts, and that raises a pathology around it. So it's better that we just fornicate as much as possible.
(One of the books I'm currently reading suggests that sexual exploration before marriage is crucial to a successful marriage because if you're never "played around," then you don't know what you like or even the basic mechanics of things, and it makes your wedding night really awkward. So this author, who grew up in the church and left it for "deconstruction" says you're doing your future spouse a favor by having sex before marriage. She seems to not understand at all that the trouble she claims waiting introduces on the marriage night is the same trouble everyone has the first time they engage in sex, even outside of marriage. So...her point is null. Not that you could explain that to her.)
Homosexuality? Why not? We are just animals following our urges. There's nothing wrong with the kind of urges that you have; you just are the way you are. (And of course, here, the world reminds us that homosexual encounters occur in nature, in animals, so there must be nothing inherently wrong with them in humans.)
Violence? That's par for the course! As animals, we are driven by our need for dominance. So when a perceived threat comes our way, it's only natural that we show our strength.
Which leads us to a few more complicated matters. Because we are animals wired for perversion and dominance, we must create laws that rein us in. We have to have gun control because we're not wired to control ourselves. We must have laws that tip the scales of justice one direction or the other because we cannot be trusted to figure out justice on our own; rather, we will always be driven by our own selfish needs.
We must have access to abortion because all of our animal fornication leads to unwanted pregnancies sometimes, and we have to be honest and say that this isn't a great place to raise a child. (Notice how the church, with its definition of marriage and family, has never had to say it's not an appropriate environment for a child...until the world came along and accused the church of "indoctrinating" children and adopted a narrative that the church is the most dangerous place for a child.)
But do you see how this all happens? First, you don't understand science. Christianity doesn't account for the basic "facts" of the world as we know it. And second, knowing what we know of science, we see ourselves as merely animals - like all other animals - and Christianity doesn't account for this either because it thinks there's something special about being human. But suddenly, because you have a Christian value system, you don't know anything about the world or about humans.
So strange that the world faults us for holding to the narrative of a fallen nature, claiming how destructive it is to the human psyche to believe you are a sinner in need of grace, but at the same time, the world insists you're nothing more than an animal and hopelessly dominated by instinct, which must be dominated by "society" for your own good.
It's enough to make your head spin. But that's exactly what the world wants.