I actually had a UMC pastor tell me, in the 1990s, that the youth pastors didn't need to teach marriage, because it was just "natural." Now look.
He himself turned out to be a closeted gay man.
Might have been bias on his part.
Still, God knew the devil would tempt people into various abuses of sex, and it was happening in New Testament authorship times making it immediately topical for the biblical epistles and for Jesus’ personal blessings on marriage and virtuous singlehood, and admonishments.
What many Christians aren’t aware of is the depths to which Jesus will stoop down to save a sinner. What we go “EWWWW — get away from me right this minute” at, Jesus patiently suffers through. It may for some be an intermediate step to shed the closet before it dawns on them that they have been lured into hateful acts.