The evidence in the article is pretty scant. I'm not sure I'd read much into "horny ladies" abounding in fiction (or joke books). My guess is that the ancients, the Victorians and we moderns are all wrong when it comes to sexual desire, male and female. Sexual desire is a sort of appetite (like hunger and thirst) but it's the only appetite we suffer no consequences from not satiating. It's subject to tremendous variability. People have different levels of sexual desire at different times throughout the day, from one week or month to another, it changes as we get older, it varies between individuals and I don't doubt that the prevailing sexual culture changes it immensely (we have to eat and yet food culture has a tremendous influence on how we satiate hunger including some cultures systematically under-eating). It's possible (although unlikely) that for many women sexual desire was a sign of a disorder in the context of the prevailing sexual culture of the Victorian era.
I'm not sure I'd read much into "horny ladies" abounding in fiction (or joke books).
They do reflect the culture of the time. A illustrative example is the play Lysistrata, where the plot is based on women denying sex to men as a punishment. This was considered hilarious because people though it could never happen. Now, cultural expectations have changed and it happened.
There was a historical shift in beliefs.
I find this very odd. How could a major cultural lineage be wrong about something so much a part of ordinary experience?
When I say wrong, I don't necessarily mean that we're right, or the ancients were right, though there's a lot of evidence that the Victorians were wrong.
My favorite theory is that people's amount of desire for sex varies sufficiently that there's enough noise to make it easy to see patterns that aren't there. I leave the possibility open that there was a change (possibly dietary) which affected libido levels differently between men and women.
People are sufficiently punitive about sex that there's going to be lies and misdirection to support the current theory about how people are supposed to be.