Joseph, a person entering the restaurant/bar does not have the right to stay until asked to leave. The CT Supreme Court defined a “Public Invitee”
“A public invitee is someone invited to enter or remain on land as a member of the public for a purpose for which the land is held open to the public.”
Thus the owners invitation to the public is to enter for the purposes of dining/drinking. The public is not holding an invitation to enter and try to convince the proprietor to change his business model.
You are correct that the owner should be contacted via phone or letter.