The beliefs aren't “beyond the pale”; using workplace resources to communicate them within the workplace in contravention to a workplace anti-harassment policy, which if inconsistently enforced poses substantial legal danger for the employer, is, however, not a prohibited grounds for dismissal from at-will employment.
"Workplace anti-harassment policy". That's the term I was looking for. Thanks.
A good simple summary of what happened:
Your employer can have an EEO-motivated anti-harassment policy. You can organize with coworkers to improve working conditions. If your organization conflicts with the anti-harassment policy, the NLRB is likely to find that the anti-harassment policy trumps your right to organize.
