Otto...I agree with everything you cited about the publics perception of Congress, but that doesn't make a comparison to polls of Bush (or any president) any more credible.
You wont find any reputable political analysts making such a comparison....its apples and oranges.....opinions regarding one man vs. a diverse group of 535.
The reasons for low opinion of Congress generally come from both sides of the political spectrum to a far greater extent than the public views of any sitting president
Members of Congress arent living up to their campaign promises
Members of Congress are using arcane parliamentary procedures to block the will of the people.
Congress is attempting to micromanage the war in Iraq
Congress is not doing enough to end the illegal invasion and occupation of Iraq
Congress is conducting a personal vendetta against Bush with all those oversight hearings
Congress is not spending enough time or taking tough enough action in oversight of Bush administration
Congress wastes money on earmarks and pork projects
Congress cut funds for a program that my district/state desperately needs
And as a result, public opinion of the work of a legislative body of men/women with conflicting and competing interests generally is lower than public opinion of the work of an individual acting in an executive capacity.
Voters also have greater means to hold the executive accountable....vote him/her out. A voter can only hold one person (or three) accountable in the legislative body.
add:
An interesting poll today that said government leaders should pay attention to polls.