I agree with Giroux on the topic of textual authorites, insomuch as I think that social networks and cultural heirarchy rules the world of academia. However, I don't know that I would back out in scope so far as to say that there is a deliniation between society, politics and such that he professes to suppose. Though it may seem reductionary, there seem to be links from everything back to social groups. And I disagree with him that the teaching of these texts is linked to developing cultural capitol, just because they are deemed "Great Books" by the textual authorities. Cultural capitol is gained through discovering any type of society, not only the books that one reads in the cannon; which, more books, from multicultural backgrounds, are finding their way into the school setting.
In reference to his interpretation of methods securing the voice of the masters--through instructing only one right interpretation to a text--I disagree. I have seen, more often than naught, teachers breaking away from this classical style of teaching. Maybe that is just my own isolated experience, but that is all it takes to start a grassroots movement. I believe that teachers are seeing this captures the motivation of their students, more than the classical method of instruction. His "fight the man" disposition can also act as a testament to the more than isolated essence of this movement.
When he speaks on texts and writing, his report offers a staunching mentality of the textual authority on the other. As aforementioned, I think that this is a trend of the past, however I do not disagree that this or any of the other views he tests have not been relavent in the near past. I for one, growing up, have seen how this plays (and played) out in the institution. As David mentions, he has seen a need for textual authority, at times: so have I. Just to think... where would one be in school without the direction of authority? Imagine going to a classroom where the teacher did not have a list of books that were commonly or socially accepted to instruct in the area of interest. It would be hit or miss. And, as David offers, it would be hit or miss. One cannot be forced to respect or assimilate textual authority. But it's good that they try.