I've seen both of these discussion points being used more and more lately, and to me they both seem to be a way of shutting down opposing thought.
When people claim that something is the opinion of "a vocal minority," they often do so without actual statistics or evidence that is the situation. When someone is arguing a point that is said to be coming from "a vocal minority," the intent seems to be to dismiss their perspective unless they can prove that they have the majority opinion, or even a significant minority opinion.
When discussing issues such as race, or gender, or sexual orientation, people frequently use the term "privileged" to silence opposing thought. For example, "The only reason you don't see that as sexist is because you're privileged." It then essentially creates an environment where people are only allowed to present opinions from members of that group.
"Wait, here's a woman who also doesn't think that this is sexist."
"Wait, here's a black guy who shares my thoughts on welfare."
"Wait, here's a gay guy saying that he doesn't think people should boycott Shadow Complex either."
Meanwhile, if any of these thoughts were being shared by a straight white male, they could be dismissed as coming from a perspective of privilege. As Janette Goering recently stated in an article discussing the "#1reasonwhy" campaign:
#1ReasonWhy is either going to be the great uniter of our times, or the great divider. We claim we want unity and equality, but if my male peers were to express the views I just have, they would be flamed to hell and back. They would be called enemies of the cause, oppressors of women. Is that equality?
So, what are your thoughts? Are "a vocal minority" and "privileged" forms of shutting down debate, or can they be useful in painting a clearer picture of an opposing viewpoint?