i am not "turned on" by "interracial" dating and i would not choose a partner based on skin color. There are many aspects to consider that are relevant, surficiality is not one of those.
But i do like to see B/w couples (both Bm+W and BW+m) in public, especially when they show a deep connection and love. And i never think anything sexual about those in a public, everyday environment. i feel there is just something genuinely beautiful about those couples without being able to say why.
As far as sex and my voyeuristic inclination goes i like watching "interracial" sex, as you put it. For me the most appealing aspect is, simply put,
contrast!
i don't see anything "taboo" about it at all, and don't believe humanity can be divided into different "races". Also most of the other ideas of possible reasons you suggest don't apply to me. ("curiosity" - you cannot be curious about anything you're already used to, "size" - what size are you talking about?, "superiority" - doesn't exist!).
It really all boils down to contrast. However for me it is
not skin-to-skin color contrast
alone. It is more a yin-and-yang kinda thing, the duality of it and the idea that "opposites attract".
i don't like the label "interracial" which is yet another stupidity the p0rn industry came up with. i would love to promote a better suited term which describes it well for me: "High Contrast" p0rn (Would "HCP" make an appropriate shorthand?). Because that's what it really is about
in my humble opinion.
This is why "white on Asian" and many other couplings do not have the same appeal and visual sensation as "Black on white" and "Black on Asian" have because it is really lacking contrast.
i enjoy watching lesbian p0rn, and a Black Woman with a white or Asian Woman makes a hot scene for sure. However it lacks the duality aspect an "opposite sex" (m+f) coupling provides.
Another aspect that ImO makes a difference and contributes to what i've said about duality are the concepts of masculinity and femininity. There are some body features that are commonly linked to either of those concepts. The most regarded of those features would probably be body-height, with "tall" being associated with masculinity while "short" in comparison with femininity. Body shape: "muscular" ... masculine, "curvy" ... feminine. Facial features: "hard-edged" ... masc., "smooth/round" ... fem. Behavior: "dominant" ... masc., "passive/submissive" ... fem. a.s.o.
A few comparative studies have been conducted in which Women were asked to rate pictures of males on a "masculinity" scale. The same setup was applied to men with pictures of females with the question about "femininity". It showed that skin complexion was a factor too. A majority of Women related darker skin with greater masculinity while there was a tendency of men relating lighter skin with femininity.
Perhaps that's the reason why Bm+W is more appealing (to me) than BW+m? Is it just me?
Just imagine... A muscular built tall Black man "manhandling" a petite, curvy white, Asian or light-skinned Latino Woman, for instance. And then compare that image with any Black Woman / white male couple having sex. - Which turns you on more?
vs.
[animated images in this post are linked in from tumblr. I do not own them. Infringement of copyright or any other possibly associated rights is not intended!]