If you judged a candidate based on a foot race but didn't make exceptions for someone who has a bad leg, then you would be discriminating against the handicapped. If a blind student is taking a test and it asks questions that rely on visual cues, then it's discriminating.
There are many things that discriminate - and standardized tests can do so, albeit unintentionally. A school - or a standard that is based solely on a test is NOT going to get you the best candidates. A test can be one measure among many, but to rely solely on a "standardized" test (whose standard?) is unreliable.
If a kid from Carmel, Indiana (one of the finest state schools in Indiana) does only slightly better on the SAT than a kids who went to Northwest High School (a notorious high school in Indianapolis), I would probably take the kid from Northwest despite the lower score, because that kid (likely black) was in the neighborhood score-wise with the kid from Carmel (likely white, though last time I went through there, it was wee bit more diverse) and did so without nearly the same advantages as the kid from Carmel. Also, if I read their admissions essays and the kid from Northwest writes a more stirring argument for what college would do for him, that would make him a more appealing candidate.
Do you see how that works? And yet, with the study you are using, you're saying it's racist to accept the kid from Northwest over the kid from Carmel, despite the fact that the kid from Carmel score higher on the SAT (and, in my hypothetical, wrote a less stirring admissions essay). Does the study account for admissions essays, GPA? Does it account for any other possible variable? Since it appears it does not, using this as an example of "racism" is merely more hullabaloo over attempts to create a diverse learning community for ALL students.
In your Dayton example: how would the black community feel if all the police officers in their town were white? If a test is resulting in everyone from a particular background failing, I would examine the test. Simply assuming that there's nothing wrong with the test and that there must be something wrong with every black person who applied - well, that's kinda what we're talking about here isn't it?