It is already being used elsewhere.

NSF grants are being rejected with massive frequency if the proposal doesn't document women and minorities being involved in the project.

I am all for diversity. I support providing minorities with opportunities to gain skills needed to excel in a certain field or make them feel welcome. Equality of opportunity is great.

Trying to skew incentives in hope that it will facilitate an inflow of talented minorities is something I've seen no proof of working. Anecdotally or statistically. If anything, it only breeds resentment.

CRA and EEOC require equal opportunity regardless of gender. California’s data shows that women are consistently being treated unequally on corporate boards. Their law reduces unequal treatment. Please define in terms of CRA or EEOC how you think this law will result in an increase of unequal treatment and thus be in violation?

Is serving on the board considered employment? What if it’s not paid?

See also California's unconstitutional gun control laws.

They believe they have moral superiority on their side and federal laws don't apply to them.