I am not sure how legal argument can work unless you show that it breaks equal employment laws. DE&I actually is beneficial in many roles such as design, customer advocacy, sales, support, UX and so on. It helps achieve a better representation of population and diverse ideas in the group. Even for managerial roles, DE&I helpful to have representation for minorities at org level. So there are a lot of provable benefits of encouraging DE&I. However, for many technical roles, for example database administrator, I am not sure how DE&I will yield same benefits. One of my pet peeve is not including disabled people in DE&I group. Most big tech only mandates racial and gender minorities for DE&I targets.
This isn't meant to target hires. It's meant to target investments which fuels alot of this. It's complicated legal stuff, and i'm just an engineer, but I think they're tackling from the mindset of "If you didn't invest in this company because it's not diverse enough, but it met every other metric on the good investment scale, then the company doing the investment went against the goals of their shareholders(more $$). The idea is that alot of the companies doing this are doing it for investments from outside parties, so by removing that incentive it should stop it.
I don't think this logic holds.
It is true that a sales rep job benefits from diversity eg having hispanic employees talk to Spanish speaking customers. However the same role can be performed equally well by a fluent Spanish speaker of any race. So a job requirement for a Hispanics sales rep would be racial discrimination for no good reason. You could construct similar arguments for most instances of diversity hiring.
Additionally Diversity is not the same as DEI. Diversity is a statistical concept whereas DEI is a religious belief
