The "spirit" I regard as the idea that anybody can express their opinion without its being either suppressed by Authority (in the reactive) or coerced by Authority (in the initiative). That pretty much calls out "fire the sumbitches" and tossing Earnest Starr in jail. It also calls out the idea of injecting national anthems into sporting events where it has no function, just because some demagogue wants to milk mob mentality.
Interesting. You avoided calling out government, instead going with "authority" (capitalized!)(twice!)
This suggests to me that you see the employer as an Authority, like government. I think that entirely misses the point of our First Amendment rights. Indeed, the First actually protects the employer's right to fire someone as a political statement.
That, to me, is the only interesting part of this issue. Should government be allowed to tell employers who they can hire or fire, and for what reasons?