Americans seem increasingly to be sorting themselves into communities of the like-minded. This new political segregation is evident in nearly all institutions of American life — from the neighborhoods we call home to the mass media we consume. It is also reshaping classrooms in America’s universities — one of the few institutions capable of encouraging civil and reasonable disagreement in our polarized nation.
Whatever your ideological leaning, this is intensely troubling. America needs ideological diversity in its classrooms, particularly in those that touch on political and social issues.
Answer: It's a problem because of people not being able to socialize, and some other things included above. ^