david gregory was the nbc news guy pressing the "mistake" issue. after the conference he suggested the president was "filibustering".
then i flipped over to abc & stephanopolous was talking about the mistake issue, saying almost exactly the same thing i just wrote: people just want the pres to admit that he is in fact human, and therefore fallible. but he won't, or can't, do it.
a few minutes later (still abc) terry moran suggested that another reason bush couldn't admit a mistake was because one of his goals for this speech/conf was to "project strength". ie, it was all about image, & even a token admission of fallibility would go against the supersoldier persona he wants to project. of course, this only served to make him look arrogant.