i think the bigger issue with having a strong preference is that it gets somehow creepy and strange very fast... i know enough people who are so eager to date only people of one specifc nation (often its japan, or korea and i bet they cant tell the difference between most asians anyway) and in the end all they do is glorifying that nation, based on whatever image they have, without spending some longer time there... ironically those are the ones that rather sooner than later change their minds, after they made a few experiences...
it is not even a compliment for the person in question, i would not like it when people like me because of my nationality...
having preferences is no big deal, everybody has them and i also dont think that there is a racist background in most cases... the fixation that often occurs is somehow a bigger deal...
as for me, i think its a difficult question... if its just about looks, sure i have one type i go for, but that doesnt mean that i exclude other types... the only ones i can think of that i dont find attractive (and i wont say that there are exceptions more than once now) are people from india and most arabs... i mean physically attractive...
but otherwise i think i go more for my type of women (and that doesnt have any nationality), if its about the looks... other i still find pretty, but i dont think i would do anything, unless we somehow get into a conversation and i happen to like her...
for dating it is even more difficult, i never thought it was possible, but being in japan showed me more or less which nations i dont get along with ( i am very happy with the cold tokyo people)... but for me the reasons are mainly in religion, behaviour and importance of family... so sure, i talk to anybody, but with most i think i couldnt have a long term relationship and that is what i am looking for...