I don't have much of an opinion about Dane Cook one way or another, but that clip was not nearly as bad as I was expecting. Also, not nearly as mean as people are making it seem. Just not very good, thats all.
But then, his material has never been that good.
As far as walking the room goes, however, if there were people following him, telling people its ok to leave toward the end of his set seems like an especially direct and shitty way to do it.