RN
Somebody watches a lot of Japanese video, notices that the women in it are less often bare than the women in American video, and generalises from that to a billion-odd people. It is a reasonable thing to notice and a bad thing to generalise from, and the gap between those two is genuinely interesting — because the thing being noticed is real, and its cause has almost nothing to do with anybody's grooming preferences.
What you are looking at is a censorship rule
Japan's obscenity statute, Article 175 of the Penal Code, criminalises distributing obscene material without ever defining what obscene means. Courts filled the gap, and for decades the answer they arrived at covered genitalia, the sex act, and pubic hair. Not hair as a modesty aid — hair as contraband in its own right.
Publishers and studios responded the way industries always respond to a vague criminal statute: with self-regulation stricter than any prosecutor had actually demanded. The video ethics body that most of the industry belonged to required mosaic masking over pubic hair as well as genitals, and that rule outlived the print world's. The government released print from a forty-year prohibition in 1990. A photo book published in November 1991 turned "hair nudes" into a national event and then a normal genre. Domestic film and video stayed restricted into the middle of that decade, and the video industry's own trade body did not formally drop its pubic-hair rule until 2006.
So for the entire period in which Western viewers formed their impression of Japanese adult video, hair was one of the things being hidden. The convention people are reading as a national grooming preference is the visual signature of a compliance regime — and a voluntary one, adopted by studios guessing at where a line was, in an industry where the mosaic is still standard today for reasons that are regulatory rather than aesthetic.
The wider point generalises past Japan. What any country's adult output shows you is what its censors, its distributors and its dominant studios permit and prefer. It is a production standard. Reading it as ethnography is like inferring how Americans dress from their sitcoms.
What the actual measurements say
There is real survey data on grooming, and it is worth being precise about what it covers, because it is narrower than the question wants.
The largest useful study is a JAMA Dermatology survey of 3,316 women in the United States. Nearly 84% reported having groomed at some point. The reasons they gave were mundane: hygiene, habit, appearance, and a partner's preference, in that order of frequency. Grooming was more common among younger women and among women with more education.
And yes — white women reported grooming more than every other self-identified racial or ethnic group in the sample. That is the closest thing to evidence the original question has, and notice how much it does not say. It is a US sample. It sorts by self-identified race, not by ancestry or country. Every group in it grooms at high rates; the differences are in degree. Nothing in it distinguishes cause from correlation, and nothing in it licenses a claim about women in Asia, who were not surveyed.
A difference in averages between large groups tells you close to nothing about any individual. Somewhere between "most" and "many" of the women in every group studied groom, and how any particular person does it is not predictable from her face.
The hygiene claim, since it always comes up
The companion study to the one above surveyed 7,570 adults about grooming injuries. About a quarter of people who groom reported having hurt themselves doing it — lacerations mostly, then burns and rashes — and 1.4% of groomers had needed medical attention. Grooming more often, and removing everything, both independently raised the risk.
That is an injury finding, not a verdict on cleanliness, and it is not medical advice; anything that looks like an infection is a question for a clinician rather than an article. But it does dispose of the framing that treats removal as the hygienic default and hair as a lapse. Washing is what hygiene consists of. The rest is fashion, and it has swung in both directions inside living memory in every country that has been surveyed.
The honest answer to the question
They do, plenty of them, at rates the surveys put in the same broad range as everybody else's. The pattern you spotted is in one industry's archive rather than in a population, it was put there by censors and by studios trying not to be prosecuted, and the only dataset that sorts grooming by ethnicity is measuring self-identified race among Americans.
Which leaves the question with nothing underneath it, and that is a better outcome than an answer would have been.