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.