In the west (especially the anglo world - which are sports heavy nations), look at which kind of men most women gravitate towards, majority of those preferred men are tall, athletic, a lot are muscular, a lot play sports, a lot are gym guys, hyper masculine, tattoos/rowdy/piercing (this is niche but still) etc.
A lot of the Black men fit into all of the above i.e. tall, athletic, dominate NFL/football (kinda national sports), gym/muscular, etc. Hence they already have physical attributes which are desirable in the west. BBC is just a bonus on top of it.
A LOT of (good chunk of) asian men are physically polar opposite to what is "desirable" physicality wise in the west, so that's already a major blow.
On top of that, pursuing sports/media/outdoor jobs/realestate/music/administration etc are more popular in the west (along with rampant drinking/drugs/partying etc. especially amongst the youth) and the culture is very anti-intellectual. Most western people don't pursue/value getting a degree in science/technology/math and going for professional jobs etc a.k.a nerdy/undesirable/boring jobs (hence the need to immigrate highly skilled people from the east). You also see VERY FEW black people in STEM fields as well, as they also don't go for such fields/job and pursue other outdoorsy/media/music etc. which is also inline with what a lot of western people love.
Asian culture and its values are polar opposite to that of the west. So, not only are asian men physically completely indifferent to what is desirable in the west, the kind of culture/jobs/education asians pursue is also polar opposite of what is attractive in the west.
Now an asian ethnic man born and raised in the anglo west might will be culturally similar to local anglo people and might be inline with pursuing entertainment/sports/outdoor jobs etc. but those asian men lose out on physicality aspect and hence many are still not desirable and also lose out on NFL/football/sports/media etc. jobs as well because no one wants to see an asian man there (doesn't cut the physicality there). Hence we don't get any representation in the media (catch 22 situation).
Basically the anglo west is polar opposite of who asian men are (both physically and culturally). South america is very similar to anglo west, just that there is no bias against asian men because there are not that many asian men in those countries in the first place.
Outside asia, there is no singular place where asian man are "fetished" or "desired". Anglo western countries are the worst and european/south american countries are just neutral (because there are not that many asian men there), so the tax of being an asian man is not that high in EU/SA, but it also doesn't mean game is on easy mode, just neutral (which is better than anglo countries where the game is on hard mode).