Let me put out a theory that is more general:
It has to do with precieved status.
In "My Barbaric Girlfriend" the girl DARES to be barbaric to her boyfriend, because she subconsciously knows that it is "acceptable" and the boyfriend will laugh it off. If her boyfriend was a white, she would not behave in such a wild way!
However, most girls would not be like that towards whites! Is this not fact? I read stories of this all the time. The Chinese girl is arrogant and condescending to any Chinese that dates her, but whenever she is in front of the whites, she is instantly meek as a kitten. This is seen all the time with whites too, the white woman who is really bit**y to the white men, would never even dare of talking like that to blacks.
The reason is because the media tells them that the "proper role" for them to play in such relationships (asian f white m, white f black m) is for them to be meek, but there is opposite portrayal of what they should behave like in same race relationships.
I have no evidence of this, but I believe this thoery is more simple and elegant than attributing it to any inherent preferences.