Femininity IS often judged superficially; that is a simple fact. However, it's not that white women are viewed as more feminine in America, it's that the plastic look is associated with femininity, and its wearers are predominantly white. The association is based on correlation, not causation. We can delve into why a "white" style is considered typically attractive, but that would be going off on a tangent. The point is, this look IS associated with attractiveness and femininity, and it IS judged negatively sometimes for this reason alone.
It's not about what I consider feminine (I never even stated my opinion on the look), it's about what American culture does. American culture IS both racially and culturally biased, and this is reflected in its ideal female beauty type. I'm not debating whether it should be, I was only making the point that it is.
You're gonna lecture me about correlation not implying causation when your argument is statistically flawed in the first place? What you're trying to do is present some sort of correlation between two categorical variables. Unless there is some way you can measure the "extent" of plasticity and "degree" of femininity on a numerical scale (and I'm sure r would be -0.9999999), no such thing as a correlation exists between these two variables.
Trust me, nobody dislikes the plastic look because it is "attractive" or "feminine". I would like to find some truth in your theory about conventional femininity, but regretfully I can't. Do separate image searches on "feminine american", "femininity", "american p*rnstar" and "trashy look" and you will find that Google Images (USA version) disagrees with you too.
You are the one who keeps basing your assumption on subjective statements. You're speaking of "american culture" as if the term only includes WASPs with blond hair. That is such a false assumption- American culture includes elements from every group, race, ethnicity in the United States. You are being subjective when you think that America thinks Barack Obama, Jeremy Piven, Noam Chomsky, Jerry Yang and Stacy Ferguson don't hold a voice or part in the American culture. I'm sure many Americans would consider your subjectivity very darn offensive.

This is quite worrying

what are they thinking?