If you start giving some people special treatment just because of their ethnicity or gender, you're going to be opening up more cracks in the system for other people to fall through - and it will hurt those people even more because they will rightly feel that the whole system is working against them personally; down to the core specifics of who they are (unfortunate individuals who don't fit under any special label).
Modern anti-discrimination approaches are often racist or sexist. They should not try to classify individuals into superficial groups, instead, they should be decided on an individual case-by-case basis based on the individual's history.
The root of injustice is simply bad luck. Ethnicity and gender are only loosely correlated with bad luck but there is no causal relationship between them (not so much anymore at least).
Anti-discrimination efforts should be aimed at averaging-out the effects of bad luck in people's lives; so that means we need a way to quantify luck on an individual basis. It's a difficult problem to solve, but it can't be solved by making gross generalizations.