At the most charitable, there's laws saying they can't actively discriminate, which is different from saying "thou shalt have a diverse workforce". You just go "We didn't discriminate based on a protected class, we reviewed everyone and decided that this person wasn't qualified for the job because of [insert bullshit reason X]."

But even if it is, so what? There's a lot of laws. There's minimum wage laws and labor standards laws, and big companies flout that all the time. I should know -- I paid for college by working a job in a major oil company that violated every labor law there is. And they got away with it because there were no jobs and your choices were to grin and bear it or remain unemployed.

One time I was hired by what was at the time the largest company in the industry it was in, and they really wanted me and nobody else so the job requirements were tailored to basically mirror my unique resume. Is some labor cop gonna come in and tell them they didn't need the perfectly legitimate looking requirements on the job ad? You could have someone else with objectively better qualifications, but they don't have the exact things I have so I'm a better fit for the job. There's lots of ways around inconvenient rules.