A Congressman represents his district... but the views of people in his district are different from views elsewhere.
It's technically possible to have a man who lives in, say, a very left-wing district in MA, approves greatly of his Democrat Congressman - whom he voted for - and a Texan who approves greatly of his conservative Republican Congressman - and both of them disapprove of the activities of Congress as a whole. Yet come election day, both of them will vote to re-elect their respective incumbent.