It's mainly convenience. In the educational establishment and some courts, equality is more important than quality. Challenging curricula on the basis "this is bad for non-asian minorities more than others" is more likely to be successful than "this is bad for everyone".<p>It is considered better for 100% of every group to be a moron than for 70% of blacks and 30% of whites to be a moron.<p>[Edit: Added words "it is considered" to last sentence. Before it looked like I endorsed this view, which I don't.]