You're right; I don't believe in it as a categorical virtue. I believe in it as an extremely useful feature of a system of government as a check against the failure mode of the leadership becoming so disconnected from the public that they fall to corruption. In short, "It's not okay for the government to turn the public square into an echo chamber."
Private people, groups, companies though? Not only may they curtail speech more or less arbitrarily in places they own, I believe quite firmly that they may respond to the exercise of freedom of speech by exercising their freedom of association and refraining from further commerce with the speaker because of the information the speaker has revealed. And with very few, narrow, specific cut-outs, American law agrees with that premise.
Private people, groups, companies though? Not only may they curtail speech more or less arbitrarily in places they own, I believe quite firmly that they may respond to the exercise of freedom of speech by exercising their freedom of association and refraining from further commerce with the speaker because of the information the speaker has revealed. And with very few, narrow, specific cut-outs, American law agrees with that premise.