@IñakiViggers As I said, I doubt the OP would care about monetary damages, they would be seeking a declaratory judgement (or declaratory settlement, more likely) instructing the bar to provide a written notice retracting its claim that the OP is a known sex offender.

@Putvi Most US jurisdictions recognize defamation per se. There are specific statutory false statements of fact (depends on jurisdiction, but usually accusations of crime are included) which are considered damaging per se and do not require the plaintiff to show any actual damages. As Inaki is saying, they may have limited monetary damages that can be recovered if there isn't any cognizable monetary harm, but a person can still use a lawsuit over them to "clear their name."

If, for sake of argument, the bar had some list they were looking at that included the OP, or included someone else that looked like the OP, that could come out in discovery and even if the OP loses the defamation case, the fact that it was a case of mistaken identity would be established in the evidence, or the OP could in fact go after the source providing a false accusation.

@IllusiveBrian yes false alligations of a crime can be, but that doesn't make it a blanket statement is what you guys arent getting

a court saying you cant make false alligations of a political opponent or biz person is not the same as your friend saying something in a bar under the law at least