I'll refrain from being a dick and talking about "not voting their interests". They have their opinions and should stick to them.
I prefer an honest labourite like TNF (not sure how rich he is) to the kind of snobbish latte liberalism that can be found in the upper middle class. Talking about union power just bugs me less than the endless talk about gun control or foreign aid.
I agree when I look at the issue the left here tend to fight for, I can only think not that they're unimportant, but that's so many more worthy things to fight over. It seem to me because the Democratic party have become so dominated by urban professionals, that their social issue are almost the only one fought over, while the really great issue are ignored.
Of course the European left here isn't much better, they too ignore fight mostly for superficial causes.