How does one determine the democratic sentiment of the public, especially a public that is pretty evenly ideologically split? Seems fraught with personal interpretation (which is arguably another form of free speech.)
I'm reminded of that old line by Tolstoy-- something like, "happy families are all happy for precisely the same reasons; every unhappy family is unhappy in its own way." The point from an Adam Smith perspective is that healthy societies might all end up tending toward the same end by widely different means: Chinese communists might achieve superior cooperation and the realization of their values as, "the good life" by means dissimilar to the Quaker or the African tribesperson. The trick is seeing that the plurality of living forms and their competing values is not a hinderance to cooperation and mutual well-being but an opportunity for extended and renewed discourses about, "what we would like to be as creatures."
Worth mentioning:
https://sites.pitt.edu/~rbrandom/Courses/Antirepresentationa...
In short-- no. Your right is to positively assert, "Trump sign" not, "excludes all other signs as a comparative right" even though this is a practical consequence of supporting one candidate and not others. "Owning a marketing company" means that you most hold to industrial and businesss ethics in order to do business in a common economic space. Being the CEO of any company that serves the democratic public means that one's ethical obligations must reflect the democratic sentiment of the public. It used to be that, "capitalism" or, "economic liberalism" meant that the dollars and eyeballs would go elsewhere as a basic bottom line for the realization of the ethical sentiment of the nation-state. This becomes less likely under conditions of monopoly and autocracy. The truth is that Section 230 created a nightmare. If internet platforms are now ubiquitous and well-developed aren't the protections realized under S230 now obsolete?
It would be neat if somebody did, "you can put any sign in my yard to promote any political cause unless it is specifically X/Trump/whatever." That would constitute a unique form of exclusionary free speech.