Shouldn't even be an issue
Granted this is just my opinion, but if something is already against state and/or federal law, like racial discrimination, it should override any arbitration clause. Anyone alleging racial discrimination is free to take their complaint to a court of law, or an arbitrator, as they deem appropriate. Arbitration could be forced for other scenarios, like someone claiming Twitler took lessons from his buddy Ellison, and is trying to cheat people out of their bonuses. However, any time something is already illegal under state and/or federal law, arbitration cannot be forced.
Still, I was sort of half-hoping that there'd be enough people they could arbitration bomb Tesla. Sort of like what happened with Uber, where thousands of people started filing arbitration complaints and it started adding up to real money when Uber was on the hook to pay the fees (because that usually ensures the outcome will be in their favor). Sometimes the little guy has more power than they think. What does it cost me to file a complaint with local regulators? A couple hours and a small amount of cash. A company is likely going to hire an outside lawyer who will cost several hundred an hour, so it's not hard to force the company to spend at least a couple grand to address your complaint. Even if you don't win outright, you get a sort of pyrrhic victory.