This makes sense when you consider the fact that getting elected to Congress is not easy -- hence members are likely to be significantly more intelligent than average. Given a fairly high prior on human hypocrisy to begin with, combined with the severely diminishing social returns on overtly displaying intelligence, hypocrisy is almost always a better explanation for recognizably "idiotic" congressional behavior than actual idiocy.
(This is not to say that Congress is especially competent; but their true incompetence tends to be of the sort common to many groups of people -- the kind that later explains failures, rather than the kind that would make them the object of contemporary derision .)
The following excerpt from an NPR story on TARP makes me feel that while the world is mad, I might have overestimated how much of that madness comes from our political leaders:
The import of this, as I see it, is that many lawmakers are pretty cognizant of the relevant issues, and that their irrational grandstanding is often a facade for the sake of the voters who think more tribally than quantitatively. The incentives are mad, but at least for now overt hypocrisy (and actual competence) is more common than sincere idiocy in Congress.
Of course, that's not completely reassuring, because if an important (but not immediately urgent) bill is unpopular, it's worth it for one party to actually oppose it and thereby gain political points. It's only in a genuine crisis that you'd see both parties actually do the right thing. (I leave it for your consideration whether TARP was indeed the right thing; but at least now I understand Harry Reid's claim that this was one of Washington's finest hours– a claim that Jon Stewart skewered mercilessly at the time.)