The criticism is that the poll, in which Bush’s approval ratings are at an all-time low, oversampled Democrats. CBS’s defense is that they weighted the numbers accordingly to account for the difference.
I think it’s fair to say that the news media use polls selectively for political reasons, but I also think it’s stupid to deny that the president has a huge public approval problem. If you want to take a press angle here, consider the effect on public approval of a press that amplifies and enhances his critics’ vilest accusations every week.