Racial discrimination is allowed in cases of Affirmative Action. AA generally occurs in two fields: employment and colleges.

For employment, the goal is to make up for specific instances of past discrimination. For example, if a city had a policy of not hiring black contractors for construction jobs in the past, that city can now favor black contractors in bids for construction jobs. A little bit of discrimination is allowed now because it's remedying a past, more harmful discrimination.

For colleges, the goal is to have a diverse classroom. Educators have made the determination that the learning experience is of a higher quality when students have diverse perspective and experiences. A person's race undoubtedly has an influence on their experiences in life. Thus, a classroom made of of one race will have a different perspective than a classroom of students from multiple races. To that end, colleges don't just took at your GPA and test scores. They consider your economic background, your extracurricular activities, and in many instances, your race.

Now, going strictly by test scores and GPA, Asian-American students are over-represented at the top. So, if that's all a school considered, many top colleges would have a huge Asian-American population. One the one hand, top scoring students deserve a spot. But on the other hand, the quality of that education will suffer from a lack of alternative perspectives. So, many schools consider other soft variables, including race. Now, it's important to note that schools CAN NOT set quotas for specific races or judge applications separately based on race only. Race can only be one factor to be considered among many. These are basically the reasons why we allow "benign" discrimination.