Earlier quoted context omitted.
Such policies are facially illegal under the National Labor Relations Act, which guarantees workers the right to engaged in protected concerted activity, such as discussing their working conditions with eachother, the press, and the public. The tweets that got these two fired were explicitly about working conditions. Google had a similar policy and, after losing NLRA cases, had to issue a notice to all employees sayi…
Except they weren't discussing their working conditions. They were discussing other people's working conditions.
Firing designers for complaining about their unsanitary working conditions is illegal. Firing warehouse workers for complaining about their unsanitary working conditions is illegal. Firing designers and warehouse workers for attempting to organize together is illegal.
Firing designers for talking about someone else's working conditions isn't "one weird trick" for avoiding the law here.