Under Title VII, an employer’s liability for [racial] harassment [at work] may depend on the status of the harasser. If the harassing employee is the victim’s co-worker, the employer is liable only if it was negligent in controlling working conditions. In cases in which the harasser is a "supervisor," however, different rules apply. If the

California law favors class actions.  So much so that Golden State courts have struck down class-action bans that show up in consumer contracts whether they apply to lawsuits, Discover Bank v. Superior Court of Los Angeles, 113 P.2d 1100 (Cal. 2005), or arbitration cases, America Online v. Superior Court, 108 Cal. Rptr. 2d 699

The ABA Journal this month includes a piece on the "enormous differences" in how federal judges "interpret the facts" of cases involving claims of bias on grounds of race or gender.

What accounts for the juridical variability?

The race or sex of the judge.

The ABA Journal item links to a couple of studies.