It is not that judges are incapable of seeing through the intellectual flaw in the "disparate impact" dogma. But that dogma is too central to efforts at social engineering to be given up for the sake of mere logic or facts.
That is why courts split along ideological fault lines in cases like the New Haven firefighters' case, where the crucial facts are not even in dispute. The only real dispute is over whether a test is automatically biased if different groups pass it at different rates. Apparently the groups themselves cannot possibly be different, according to "disparate impact" theory.
Facts play a very small role in such issues-- including the facts as to whether social engineering-- especially a lowering of standards for blacks-- actually helps blacks on net balance. But empirical studies indicate that black students do better at colleges and universities where their qualifications are similar to those of the other students at those institutions and worse where they are admitted with wide disparities in qualifications.
Where in fact have blacks been most successful? Sports and entertainment come to mind immediately. These are areas where blacks have to meet the same standards as anybody else.
If Derek Jeter swings at three pitches and misses, he is out, just like any white ballplayer. If people stop watching Oprah Winfrey's program, it will get cancelled, just like anybody else's.
The biggest beneficiaries from the "disparate impact" dogma are those who claim to be helping minorities. They benefit by feeling noble, winning votes or attracting money. The actual consequences for blacks-- or for the polarization of American society-- seems to be of little concern.