This really does not fall into working conditions, in the legal sense of the word. "Musk is an asshole because of how he tweets" says nothing about the working conditions of SpaceX.
If the letter alleges that Musk directly harassed employees, that would be entirely different. But it doesn't; it merely says that Musks behavior in the public sphere is unpleasant (again, that's fair).
If the letter alleges that Musk directly harassed employees, that would be entirely different. But it doesn't; it merely says that Musks behavior in the public sphere is unpleasant (again, that's fair).