EEOC makes it illegal to discriminate based on race, color, religion, sex, national origin; why can't political views and speech said outside of the workplace be a part of that?
Free speech protects you from the government, not your peers.
So, yeah, I'm pretty sure he violated that. And Blizzard's response has too. It's really just a catch-all trivial to violate provision.
As a separate note, the player and hosts would likely be considered to be contractors, not employees.
If you try to sue someone for violating a law that doesn't exist, they will make a motion to dismiss for failure to state a claim, and the judge will throw out the lawsuit.
That's not to say it is right or acceptable, but it isn't illegal.
Source: https://www.nolo.com/legal-encyclopedia/can-employers-discri...