I work for the Roman Catholic church in the USA. I am an administrative assistant with only very rare dealings with the public. When I was hired I was told by a Human Resources representative that if I was seen "holding signs" (direct quote) advocating for any of three political issues my employment "will end." The issues were LGBT marriage, reproductive rights, and euthanasia.
The implication was that it did not matter whether I was on or off the job, or whether I was representing my workplace; if I held signs advocating for any of those things even on my own time and with no direct ties to the organization or church, my employment would or could be terminated.
Is this legal?
I can understand forbidding it when "on the clock" or if I was wearing a shirt that says "I work for the Catholic Church," but controlling my own personal freedom of speech seems very illegal or at least strong grounds for wrongful termination.
Any help would be great. Thank you.
Related: Can an employer require employees be Christian? From this I know that religious employers are exempt from discrimination laws, but I'm not sure how it applies to my situation.