Notice they were bringing the girls to London. So while you’re comparing Japan to third world countries the problem exists everywhere. The middle east seems to be driving a lot of it with their unlimited check books.
We’ve all seen the estimates of sex slaves brought into the US as well.
The Japanese have a hankering and fascination for fair Western women with red hair especially and blond too. This is reciprocated by American/European men being drawn in by the femininity of Korean and Japanese women. So it’s a draw I guess. Japanese never enslave girls who go there.
The Arabs do as you have said. There is lots of white slavery going on in palaces, yachts anchored in Mediterranean party ports and with the oil rich sheiks. And by white slavery I mean white women with the fair and Nordic ones most valued. Hopefully more white women are wary of rich Arabs these days. They will be treated very nice then treated like shit once they been spirited into their harem behind high walls