What elite schools value URM the most?

OP’s question neither implicitly nor explicitly suggested trumping race over merit. (Indeed, at MIT that would be ludicrous.) OP’s other threads have addressed areas such as test-taking and specific programs at various universities. Maybe you could review those threads.

A great many schools are looking for a whole package–accomplished, intelligent kids that are diverse in many different ways, including race. So a question as to any of these factors is legitimate IMO.