Nutter didn't say these things in order to reinforce stereotypes about Philadelphia to a national audience - he's saying them to *us*, the citizens of Philadelphia and his likely future constituents. He's telling us he needs our help to change a fundamental attitude about the city - that things will never get better, that mediocre is as well as we can manage, that there's no hope trying because we're doomed to fail.

Frankly, it has nothing to do with a national audience. This is for internal consumption.