If you have any sources beyond "IMO" I'd be interested. Until then, I'll consider the correlative data to possibly have merit at least worth consideration and further (personal) investigation, especially since it was never stated or even suggested to be definitive or a universal phenomenon. The article is also anything but comprehensive, so I think you'd need to review the actual data to debunk anything.

Edit: I also never stated this was the sole and definitive cause, only that it may explain it. I'm a scientist, I know better than to definitively state just about anything, even in my own field, but I'll still share interesting articles without busting out a MANOVA.

The article outlined reasons for that to be happening in Japan, and references India for similarity, it didn’t imply that that is a universal response to gender inequality, simply that the reason for that specific phenomenon in Japanese culture is likely because of gender inequality, which seems more than a reasonable conclusion to me, especially when you look at the 80’s business woman culture era and how there was a decline in that specific behavior.

Also, I’m very much not seeing what you’re saying about your interpretation of feminism being present in the article. Gender inequality is a thing, objectively, to address that as a part that plays relevance in any given context doesn’t require feminist values.