Gotcha. My anecdote about a family member (not an uncle, BTW) is irrelevant. Your unsubstantiated impressions of general workplace practices, on the other hand, carry the day.
I can't believe I let you Tom Sawyer me into doing more research, but I did — and Griggs was interpreted to apply to any employment qualification, including college degrees, professional certifications, etc. – just like the Chief Justice said. Surprise surprise.
I certainly think we're all correct that college degrees have become vastly more important 'markers' and 'signals' for most jobs than they were 40 years ago. That's probably because we've dumbed down secondary schools for political and cultural reasons, but that's a hugely complex question and well beyond the point of our disagreement.