Robin,

Some brute preferences and values may be inculcated by connected social processes. Social psychology seems to point to flexible moral learning among young people (e.g. developing strong moral feelings about ritual purity as one's culture defines it through early exposure to adults reacting in the prescribed ways). Sexual psychology seems to show similar effects: there is a dizzying variety of learned sexual fetishes, and they tend to be culturally laden and connected to the experiences of today, but that doesn't make them wrong. Moral education dedicated to upholding the status quo may create real preferences for that status quo, (in addition to the bias you mention, not in place of it) in a 'moral miracle' but not a physical one:

http://lesswrong.com/lw/sa/the_gift_we_give_to_tomorrow/