You wouldn't wait until you're married before meeting her
parents, so why should you wait before meeting her genitals?
There are reasons, and they have already been addressed in this thread. Whether those reasons are sufficient or applicable to any particular individual is something for those individuals to decide.
To recap:
1) For many people, possibly even most, sex is an emotionally significant event. The first time imprints them in several ways. When two people imprint on each other, that creates a potential for compatibility that is very difficult to achieve in other ways. You speak of sexual compatibility, but while trial and error with lots of people in one way to "find" it, it can be
created between two people who share their learning process about sex together exclusively with each other.
2) The concept of
inertia applies to behavior and psychology just as much as it does to physical objects. If one wants to have an exclusive relationship eventually, it makes practical sense to become accustomed to such a lifestyle. If a ball is sitting on a pool table, it doesn't magically start moving on its own. When I hit it with a pool cue it will tend to stay in motion until something stops it from moving. Inertia. If you live your entire life planning to have a relationship with only one person, and then meet one person and marry that one person and have sex with that one person, you've living a lifetime of consistent behavior that will tend to more easily continue to be consistent in that behavior. If you have casual sex with different people whenever you meet someone sexy, once again, you're creating a pattern of behavior that will tend to continue. Living a lifestyle of casual sex with whomever you want and ending relationships whenever they become inconvenient, is not a lifestyle that is easily conducive to lifelong commitment. If you want to someday have a relationship that involves lifelong commitment, it's helpful to have psychological inertia conducive to it.
3) Additionally, while it hasn't been addressed that I've seen, there are a few less "nice" reasons resulting from, for lack of a better way of phrasing it, human frailties. For example, if you've had sex with 10 people, and then settle down and get married, it's entirely likely that the person you marry might not be the best of them in bed. That has the potential to weigh, not only on you, having sex with someone and after a few years becoming increasingly disappointing that they don't live up to the better sex you used to have and now miss, it also has the potential to weigh upon them, because they know that you've had sex with nearly a dozen people, they know that the odds are that they're not the best, and it's difficult for them to be sure how honest you're being about it. Whereas, if two people have only ever had sex with each other, they both
know that they're the best sex their partner has ever had. There's a very real and significant feeling of security and certainty that can result from that. There are lots of issues of this sort that sex-with-only-one-person-per-lifetime enables one to avoid. What about penis size? Mathematically speaking, half of the entire male population has a penis that is in the bottom half of the pool of penis sizes. "Below average." If a girl has sex with 10 guys, then marries one, it's extremely likely that she will have had sex with guys with a bigger penis than her husband. How will he feel about that? Once again, if two people have only ever had sex with their one partner, that will never be an issue.
Granted, none of this has anything to do with
marriage specifically, and I'm not arguing in favor of the rationalizations given by the article in the original post. I'm not suggesting that anyone requires permission from a preacher to do as they choose with whom they choose. Nevertheless, there are some definite benefits to lifetime exclusive sexual partnering.