Why use various proxies at all? Most of the group differences seem to largely share poverty as a primary root factor, and this impacts plenty of sub-groups within the supposedly advantaged groups as well. So why are we not simply addressing that directly?

A refrain I've been seeing a lot lately is that the outcome of a system is its purpose. Perhaps that reasoning should be equally applied to an analysis of the implementation choices made by various social programs and the solutions espoused by various political movements.