Your analogy is not at all applicable. According to the American Cancer Society, men should start considering getting a prostate exam at age 50. Therefore if a 23 year old male is NOT getting a prostate exam, then he is doing exactly the right thing and still has a low risk of prostate cancer.
However, adults of ANY age who are sexually active (again, excluding monogamy, if you want), SHOULD be getting tested for STDs. Therefore if a sexually active 23 year-old female is not getting tested for STDs then she is NOT behaving responsibly, and has a much higher risk of having an STD than the older female, who has had more partners, but is tested regularly.
tl;dr- Base rates
You're disputing a contingent aspect of the analogy that isn't related to the problem with the OKCupid article.
To establish that "older people get tested more -> older people have less undetected disease", you first have to establish that older people started out with the same base rate of disease as younger people. The OKCupid article doesn't do that, and knb is correctly calling them out on it.
I agree that younger people in fact have higher STD rates than older people, but OKCupid makes a fallacious argument for this, and it is acceptable in philosophy to criticize fallacious arguments for true conclusions.
Why don’t men go for younger women? That’s not quite accurate, because they do, but we seem to have a cultural norm against girls who have recently exited puberty, even though they are highly fertile. Some time in the last few hundred years, we reached a cultural norm that as a man gets older, it’s increasingly less appropriate for him to be with a sixteen year old. That’s not long enough to override thousands of years of evolution, so what could have contributed to it?
The best solution I’ve heard started by looking at who benefits from this norm [older women] and wondering whether they could have contributed to it. After all, the strength of this norm has been increased in the last sixty years or so, which coincides with the period in which women’s power has increased.
One alternative I heard recently is that it doesn’t make sense biologically to go for women who are recently post-pubescent, as they don’t make the best mothers. Instead, a slightly older woman [mid-twenties] makes sense to be the best mother. This is perfectly plausible.
Another, less plausible, suggestion I’ve heard is that it’s to do with mental capacity. I find this unconvincing because we have few objections to a high-status man dating a beautiful but low-intellect woman.
Thoughts?