All kinds of other possibilities occur to me, other than the "repressive hypothesis". In no particular order:
Women actually were the hornier sex in antiquity, but something in the Western diet changed our hormone balance.
Women actually were the hornier sex in antiquity, but some disease (the Black Plague? syphilis?) selectively killed or rendered infertile the horniest women and/or the least-horny men.
The claim that women were the hornier sex acted as a justification for rape: "that slut wanted it!" writ large. Since women didn't write the histories, we have no idea what they thought of this claim. As the status of women rose from near-slaves to near-equals over historical time, this claim has been increasingly untenable.
The claim that women were the hornier sex was reported by the tiny fraction of men who were literate, who also tended to be the highest-status, best providers, most well-spoken, most artistic, having the most leisure time, best-fed. In other words, among the ancients, the literate men (who wrote the histories, the plays, etc.) were by far the most attractive to women. We don't have any records of whether illiterate ancient men, who were the majority of the population and who were less attractive, also believed that women were sexually insatiable.
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.