This is a rare occasion where I don’t fully agree with you. I would draw a clear distinction between a person (whether employee or business owner or whatever) and the business. The person has free-speech rights, the business (as I see it) does not. Thus, when acting in their business role, the employee does not have free-speech rights. If the business offers a general service of messages cakes for all comers, then it should not decline if the message is one an employee does not like. Even though the message is added by an employee, the “speech” is not theirs and they should not veto it.
This is a rare occasion where I don’t fully agree with you. I would draw a clear distinction between a person (whether employee or business owner or whatever) and the business. The person has free-speech rights, the business (as I see it) does not. Thus, when acting in their business role, the employee does not have free-speech rights. If the business offers a general service of messages cakes for all comers, then it should not decline if the message is one an employee does not like. Even though the message is added by an employee, the “speech” is not theirs and they should not veto it.