I used to have a Korean "friend" whom I hung out with. He would go out to lunch or dinner with his Korean buddies. He told me I couldn't come because it was a Korean thing. That, I thought, was reasonable because everybody should have the chance to be with people they think they have something in common with.
Then one day I found out they invited a white guy to go to lunch with them. I asked him why the white guy could come when he had said it was a Koreans only event. He tried to laugh it off and he said he didn't notice that [the white guy] was not Korean.
This sort of incident was to repeat itself over and over. Different white people who usually don't hang out with members of the Korean group would get invited to go to lunch with them, not often, but at least once or twice. Never was another person of color invited, not even if they were supposedly close friends with Korean individuals in that group.
That Korean "friend" revealed over time ignorance and disrespectful attitudes towards Southeast Asians. He would ogle waitresses in Vietnamese restaurants and pass lewd remarks to other male patrons. Korean women were "wife-material" and non-Korean women were viewed as sex objects.
I confronted him about his attitudes towards Southeast Asian women. He very readily chose to terminate the "friendship" instead of holding an honest dialog about his racist dehumanizing attitudes.
I realized he was just using me when he was new to the USA and needed someone to show him around. After he gathered his group of Korean friends, I was easily disposable.
The Korean scorn towards the Vietnamese (and other non-whites) is well-known. 48 Hours ran a story on poor labor conditions at Nike factories in Vietnam in 1996. In addition to subjecting the workers to horrible material conditions such as allowing them only 1 toilet break and only 2 water breaks every 8 hours, Nike employed Korean supervisors who regularly insulted and harshly scolded the Vietnamese female factory workers.
I agree with T's observations because I know from personal experience that Koreans (and also other East Asians like the Japanese and Chinese), look down on Vietnamese and other Southeast Asians. Many Korean men look at Vietnamese women in a very demeaning way. That's not to say that they are very respectful of Korean women, but they still consider Korean women superior to Vietnamese women. To many Korean men, Vietnamese women are nothing more than, as T put it, objects not deserving the respect due to other humans. Some Koreans only seem to be nice only to whites and other Koreans.
There are the people who say, "Oh we love Filipino food, we love Vietnamese food, oh we love Thai food", but they have NO respect for Southeast Asian people.
My boyfriend's brother (Korean) would have liaisons with black women and white women. His sister disapproved of all these women. Only a Korean woman was acceptable. But he is not serious about the black women and white women anyway. He would say, "They think they're my girlfriends, but I never told them they are my girlfriends." He only planned to marry a Korean.