How do you know in any given place who are the marginalized, the oppressed, or the minority? Look for the groups who change titles every five to ten years or call themselves something different than what outsiders call them. What does that have to do with anything? The ones in power decide what the ones without power are named.
And that does not even need to be directly. A marginalized or stigmatized group will eventually have its name associated with the negative things people think of that group. It's gonna happen. They're marginalized. No power means that people won't know very much about them. They won't be seen as individuals because they are segregated to their own communities, e.g. mental hospital (In this case, even where they live has a name change). The majority does not have any contact with these people unless one or more of them does something newsworthy, and that usually means something negative. A black man is arrested for drug possession. A special ed child soils himself in class. A mentally ill woman harms someone else. So that's how the entire group is labeled. Addicts. Stupid. Violent.
