Bottom line is that there is no right to free speech in a private workplace. We have decided, through Congressional means, that people shall not be discriminated-against in the workplace. Further to that, the owners of the business have the right to emplace further restrictions, and cannot relax those governmental guarantees of equal treatment.
"Free speech" as codified in the Constitution doesn't apply to private entities.
"Free speech" as codified in the Constitution doesn't apply to private entities.