Since Griggs. [0] You can't do broad-based testing such as IQ or IQ-proxies (SAT or ACT). This is why companies have shifted to hiring based on degrees.
The argument they cops used is that people who score to highly on the qualifying exams are likely to become bored with the work they do faster, leading to a lot of turnover and the costs that go with replacing them.
I'm seeing this claim everywhere recently. By any chance, did you see it fairly recently, maybe on a SlateStarCodex-related community?
As indicated in your link, IQ tests and diplomas are treated the same way by Griggs: they are okay when they are a reasonable measure of job performance and not okay when they're not.