Invisible Hand?

Why does it seem that the most ardent advocates of the invisible hand (I refer to them as "Market Huggers") are also the loudest proponents of treating certain income more favorably than others?  Why should capital gains, dividends, "carried interest", etc., be given better tax treatment than ordinary income?  If money flows where the invisible hand directs it, then why does some activity need extra tax incentive?  The theory says that the risk/reward trade-offs will be compensated exactly as the market says they should, right?  Or don't you really believe in your theories?  It sure seems to me that saying certain behavior should be treated with this extra subsidy is an admission that the theory really doesn't work and that you really don't believe it.