IMO if a western man prefers to date only, and ONLY Japanese/Asian women, especially when he has never lived in said country, it is solely because I believe he is brainwashed by the culture of anime, manga, misleading blogs and the internet as a whole, and maybe even by the porn so prevelant on the internet today etc. Such a man is uncultured and is only following a fantasy that will inevitably lead to disappointment in the long run when he runs across an independent Asian woman who will slice him to threads and burst his bubble.
As I've said in previous threads, sure, there are women who fit the mold of the docile, subservient woman who puts their man on a pedestal and always will as that is the culture of Japan, but it is by no means the norm in modern Japan today. These stereo-typical women usually do not seek out foreign men and prefer their own kind and will usually never marry a foreign man nevermind date one unless they happen to meet by chance and "hit it off" so to speak. Of course one may find this rare woman who does fit the mold of the "typical Japanese woman" and will marry a foreign man, but it is rare and if one of these marriages succeeds in the long run, it is truly an accomplishment.
In my own case, I married a Japanese woman and preferred dating them because, as Frustrated Dave alluded to above, I had no other option. I lived there! Foreign women were very few and far between and were rare and those few that I did meet were already taken and the rare two that I dated we just did not hit it off as the "spark" was not there. Besides, I was living in Japan at the time and had no intention of leaving and they were just passing through.
Don't get me wrong here, and I will be honest, if given the choice between dating a Japanese/Asian woman or a western woman, and all things being equal, I would probably choose to date the Japanese/Asian woman because I personally find them visually attractive and have far more experience with them than I do with woman my own race. Why? I cannot explain it. (And yes I have also dated a Korean, a Chinese, and a Thai woman. All in Japan)
However, on the other hand, there are many a foreign women that I also find very attractive if they have dark hair as that is just the way I am and I cannot explain it. I am just attracted to dark hair and if the dark hair is on a Japanese/Asian so much the better. It's just me and the circumstances that perhaps "molded" my thinking.
But, looking back on it and being completely honest with myself, I was ALWAYS attracted to Asian women from the time in the US I first discovered women around puberty! Again, I cannot offer any logical explaination for this weird attraction at such a young age and with hardly any knowledge of Asia and their women and culture. It was just there and ending up in Japan was a dream come true. There may also be some western males like myself who also have this same, odd attraction to Asian women for reasons they themselves cannot explain.
However, in my own case, while in Japan, I did not prefer the demure, docile, submissive, stay-at-home stereo-typical Japanese woman that so many western men seem to look for as that was not my type and I did not seek them out. In fact I avoided them at all costs. However, I was lucky enough to meet an independent one who would give any western woman a run for their money when it comes to independence and not fitting the Japanese mold. In this I feel I hit the jackpot, so to speak as I have the best of both of western and Asian culture.
However, and I do not have the time to go into it here, while remaining independent and working, she still retains some of the Japanese culture in that the man should not do certain things like cook and clean even though I insist on it as she holds a full-time executive job to boot!
Over the past 28 years since we've been together, I've just given up on trying to "help out" around the house and just do the "manly" things like mowing the lawn, fix things, take out the garbage, take care of the cars, etc and accepted it and, in a word, it is "paradise" (to me anyway) and it has worked for us.
Could I date a western woman and maybe remarry should I suddenly become single? Yes I could as I prefer to look at the whole person and what's inside them rather than just their race or ethnicity. However, they would probably have dark hair!