[neilk]

You're right that most consumers don't really act like it's a priority for them, even when labeling regimes exist and they have said that ethical products are important. The best you can get is a 10% premium from a segment of relatively wealthy and socially conscious people.[1]

However, for those that do, I'm not sure "self-righteous" is the right term. I think the word you were looking for was "non-hypocritical".

Anyway, I think this just shows that the checkout counter isn't the right place for us to exert our ethical standards. When no one's really watching, and the pain is significant, we're weak, atomized individuals. We even know that our individual purchasing decisions mean zero to giant economic forces. So it's rational to just go for the lower price. All progress with labor standards have come about in other ways - journalism, legislation, and unionization.

[1] http://www.people.fas.harvard.edu/~hiscox/Depelsmacker.pdf