I thought it had something to do with certain Christians having a negative belief about sex.
For a while, it was popular to "kiss dating goodbye". Along with the idea that you should only date the individual that you intend to marry. Maybe some are still saying this. Who really knows these days, however, as such extra-Biblical things led me to stop taking mainstream Christian culture seriously.
Since when is committing to "court" somebody before you have a sense of who they truly are a good idea? It boggles the mind. Sure, sometimes two people see each other across a crowded room and that connection lasts a lifetime. However, they're the exception to the rule. The rule is shown in the contemporary Christian divorce rate.
If anything, we should kiss dating hello. Just be responsible about it. Dating doesn't have to be sinful. Its values are simply the values of the two individuals involved. This isn't rocket science, but with so many looking or excuses to act like nonbelievers I can see how there might be a problem. But then again, who are they fooling? The assumption that it has to be that way is mostly projection in my opinion. The "kiss dating goodbye" attitude says more about the person saying it than it does about dating itself.
It could be that too. I get greatly irritated when some Christians act like prudes. Even worse when they make a show of it as if it's something to be proud of. Perhaps it's a way for asexual people to fancy themselves as better than those of us with a sex drive.
That sort of thing discredits the Faith as a whole. And it makes us all look like uptight ding dongs. There's nothing holy or righteous about prudishness.
Maybe I'm a prude, who knows, but I don't make a show if it in real life. It doesn't make me holier than thou, but it does help keep me out of trouble. My life is simply simpler and more manageable not looking like a soap opera. The libido isn't lacking, but the cons of extramarital sex outweigh the pros for me.
"Prude" comes from the word prudent, which describes how I envision my best self. That is,
"Acting with or showing care and thought for the future." It's what strength looks like in practice and how I strive to be with God's help. Few will reward you or pat you on the back for making prudent choices. The rewards are intrinsic and don't depend on outward approval.