By my count, this post includes critiques of four weak right-wing arguments (abortion, euthanasia, taxation, affirmative action) and three weak left-wing arguments (eugenics, sexism, capital punishment)

I was surprised people didn't notice that both the sexism and eugenics arguments where somewhat "right wing". I think a key thing might be that perception of "right" and "left" are tied to the current American political landscape. The important role of religion in it means that conservative politicians don't often make arguments for their policies based on evolutionary psychology or the high heritability of IQ or conscientiousness. The America right seems almost as invested in blank slate notions as the left.