> I also believe that they explicitly give preference to certain groups of people over others. So what is the point here?
You give the example of the journalism, geography, and ethnic studies departments specifically seeking minority viewpoints.
FWiW I don't think the DEI corporate and other programs in the USofA have been particularly well executed, they appear (from afar) to be more performative than substantive, however ...
The three examples you gave should more or less answer your own question for you.
Journalism, good reporting, brings deep informed insights from the ground. That's not going to happen when reporting on foreign countries and disadvantaged communities if all the reporters are (say) from a WASP background and perspective.
Geography isn't just maps, there are strong elements of people's relations with land that are part of that domain .. again a breadth of viewpoints gives richer coverage.
Ethnic studies. .. I mean does this really need a comment as to why diverse viewpoints deliver broader outcomes?