>>42690320Well, at least for japan, its cause for a long time only hookers wore underwear, it was a western concept, and hookers took to it cause wearing expensive exotic foriegn lingerie made them look like higher class hookers, which were more desirable, meaning more clientele, better quality clientele, and steeper prices.
so they got kind of an inherently sexual connotation to them. More so even than nudity til they became more widely adopted by average women. To kind of translate that in your mind, compare normal everyday practical panties and bra to like, a really ornate and well-made one of those belly dancer getups, or some skimpy translucent silk and gold ancient egyptian/Dejah Thoris/Slave Leia/Tyr'ahnee bikini. Even with more covered up, the latter is much more alluring. In comparison, the former looks mundane to downright trashy.
most things degenerate about japan are either left over from ye olden pagan days, or a result of them trying to mirror western and especially united states sensibilities but ending up one of those like funhouse caricature mirrors, ESPECIALLY if they tried to have their cake and eat it too, whence came things like tentacle porn as a way to abide by draconian censorship laws by invoking some old folklore for substitutes.