There's a natural instinct to spread seed widely (it's just biology), and so "exotic" is a "target", if you will. Were in the west, "exotic" seems to mean Asian more than other ethnicities simply because of population differential. Pair that with the fact that the pornography supply is huge coming from Asia (again, a population thing), and you have a stereotype just waiting to emerge. Not good, but it's a logical outcome.
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Typically there's a built-in control mechanism where you're most biologically attracted to someone who's quite genetically similar to you that you'll be spreading more of your genes but not too close so that you can add variation and pick up improvements.
Doesn't work quite so well these days when most of us are spiteful mutants, fed and happy, and regularly mix in very expanded genetic pools.
There's both, I think. An instinctual aversion to too foreign is a health thing, just as aversion to too familiar. Likewise, instinctual attraction to somewhat familiar or somewhat foreign are for the support and spread of genes. There's a balance or tension between the two phenomena.
