At will employment doesn't matter here. Even with at-will employment it is illegal to fire employees for some reasons. For example, it's generally against the

At will employment doesn't matter here. Even with at-will employment it is illegal to fire employees for some reasons. For example, it's generally against the law to fire employees for discussing their work conditions. I think the employees will have a difficult case here, but it is conceivable that some of them might. For example I could see the NLRB ruling in favor of an employee who was fired after for expressing concern about a project with Israel, but I think the employees who staged a sit-in probably don't have a case.