Teacher - Student Power Struggles

The Gutierrez, Rymes, and Larson text discusses the power dynamic between teachers and students. The text reports a scenario when the observed classroom discussion briefly enters the third space. The teacher is portrayed as uncomfortable and attempts to bring the class discussion "back on track" by steering the conversation away from "half black/half white" topics. The explanation perceived by the observers suggests that "the opportunity for contesting class standards, such as the history of racism in this country or attitutdes about miscegenenation, goes unheeded" (466). I agree that the 'off topic' discussions often become the most valuable, and culturally or socially relevant discussions for students and teachers to learn, but it depends on other factors. If members of a class are developmentally immature they may not be prepared to discuss certain topics without the possibility of offending others. I'm not a fan of censorship, but occasionally there are moments when I believe it is my duty, as a facilitator of discussion, to sway the conversation from becoming harsh or offensive. Thoughts? Anyone agree or totally disagree?