In particular, owners of bars, restaurants, stores, etc., face legal pressure and sometimes not legal pressure every day to do stuff they'd rather not have to do, "rather not" because it negatively affects their business, their customers (such as via higher prices than maybe the next jurisdiction over), etc. Been there, done that. They decide whether to comply vs. just pay a fine (sometimes repeatedly), risk getting closed down, and so on. If you don't like their decision, if you were polite, you'd phone them (nicely) or write them a cordial letter stating your position. Instead, you are on THEIR property, potentially risking trouble for them. Which property ownership obviously you do not respect.
Now, why don't you go ask (ASK!!!) the owner or their representative if the ownership is in favor of or not in favor of requiring masks to enter. Regardless of their reason, if they say yes, and you are passionate about it, respect their decision and don't go in, but please feel free to advise them in writing why you are no longer a customer. If "no", try to work with them to organize a large (large!) protest at the business or maybe City Hall (owner's choice), not against the business itself, but supporting it and against the local officials, notifying the pertinent officials and news media well ahead of time.