The "culturally biased" excuse was born from a handful of questions which have long been deleted - the most famous being the one that looked for an analogy for "runner : marathon" and the best answer was "oarsman : regatta." That would also seem to be biased against the much larger population of poor whites that didn't know much about sailing, but then again, we are dealing with a mindset where the perception is that all white kids grow up using the family yacht, when they aren't networking at the country club.
The "culturally biased" excuse is debunked. Attempts actually have been made to argue mathematics and the scientific method are inherently "culturally biased" (i.e., racist), but they are not credible or even coherent. Neither has anyone accounted for the fact that we are not anywhere near as segregated as required by the "culturally biased" claim - all kinds of kids of different races and backgrounds go to the same schools all around the country. Most of us know that from our own experiences, especially in city schools. Neither has any credible attempt been made to account for why the "culturally biased" tests don't have anywhere near the impact on poor whites, Asians (quite the opposite!), or Hispanics/Latinos that they do on blacks.
Over 50 years now, all that gets repeated is that SAT/ACT must be "culturally biased" against blacks. We are at the point now where we just basically say that any testing of logic, reason, deduction, vocabulary, and math in and of itself, is biased against blacks and we need to just eliminate the idea of standardized testing altogether (why not just eliminate it for blacks?). Grades will soon fall as indicators of anything, as some have already noted. Welcome to the age of reason!