It's not just Caucasian, it's all non-East Asian. So even Southeast Asians will get denied if they are little too dark. Had this happen to a Philippino and Korean monger. I get Mugi's point about culture. It's also a bit about exclusivity. Ive been with more than a few girls that work both Asian only places and Foreign friendly ones. Even tried to get them to hook me up but they said it just wasn't allowed at the Asian only places. The ones with a good grasp of English mentioned culture familiarity, like Mugi said, also language and perceived safety/comfort being motives for the ladies. For the guys though some mentioned it was about exclusivity, not having to share or deal with "foreigners". Its just that usual bias that everyone falls for to an extent. Granted it's not all their clients thinking like that but it's enough when you are in an area like flushing. An important aspect if the girl is there to make money and many of these Asian only places get way more traffic than the Foreign friendly ones. At least that's what I was told. So some chicks prefer to be open to foreigners more so because the place can be less busy and work less taxing through a full day. Others will go for the money. Just another factor I've heard about not the full story ofcourse.
Ain’t that the truth.
I experienced something a bit similar amongst the girls that surprised me in a Chinese House back a long while in Flushing. It was back in the day when Flushing was just sprouting, happy and carefree.
I once went to a barbershop-front place in the Flushing hub where it was run by Mainlanders. It was a small barbershop set up for other Mainlanders.
After my haircut, the girls congregated around me and asked if I wanted massage. I tried to pick one of the pretties that were available and the Mamasan denied me.
But, she sent me to another room upstairs with a much darker Asian girl who was by herself, not congregating and speaking Mandarin fluently with the main group of girls.
She was cute enough for me. But, she looked kind of depressed. We had a nice session together and I asked her why she was so blue.
She told me that she is not from the Mainland, but from Southeast Asia, and because she is much darker, she is treated very poorly and not accepted in the group.
I was kind of just learning about the cultures and just perceived Asian as Asian, but learned that it was not so.
Go and figure, just a few shades darker in pigment.