I agree that the goals are worthwhile, and also feel that requiring every proposal to include this is not efficient and/or very effective. They should take all the funds and time spent on this every year as part of every award, and just fund programs specifically designed to attract inner-city kids to science, or funnel talented, low-income, high school students to be mentored, taught advanced classes, etc.
I would be happy to spend time mentoring URM, etc. But it'd work a lot better if others managed such a program, thought about how to attract them, etc. Specialization is good.