Earlier quoted context omitted.
No, that is the opposite of what the NLRB found. It's not quite as simple as political affiliation being protected (although in California it might be), but rather that under the NLRA, you can't be fired for the act of organizing to improve workplace conditions. The Advice Memo explicitly states in several places that had the Damore memo not advocated in favor of stereotypes against women --- something that is itself…
Simplified: He actively advocated for discrimination against a protected class (women). There was no way the NLRB was going to find that to be protected action. The ramifications if they had would be that if someone creates a discriminatory workplace a company could be sued by both the victim and the violator. Under such a rule, both people's rights would be 'violated'. The point of rights is to protect you, its not…
Women are not a protected class. Sex is a protected class.