At public schools in the US, quota systems are officially illegal (UC Regents v. Bakke), but they are allowed to use admissions to encourage diversity (Grutter v. Bollinger).
In general, both public and private schools tend to over-admit minorities (in proportion to their presence in the population), so from the other perspective, are discriminating against majorities.
In general, both public and private schools tend to over-admit minorities (in proportion to their presence in the population), so from the other perspective, are discriminating against majorities.