Except preferential treatment backfires.

People will think “if XYZ group has a handicap maybe it’s because XYZ group is genetically inferior?” XYZ members themselves will think that and it will subconsciously affect them. People around them will think that and it will subconsciously affect their opinions towards them.

If you point out that XYZ group is only handicapped because they’re statistically environmentally disadvantaged, then it follows, why not handicap everyone with that disadvantage, or any comparable disadvantage? Why not handicap ABC minority? Some members of ABC will be jealous of XYZ and subtly discriminate against them (for this reason; these members would otherwise).

It creates the background conditions it seeks to destroy. Instead, handicap on things like health and income, which are more obviously fair and necessary (most people can accept that bad health and income are an especially serious disadvantages in today’s world).