It seems it wasn't just a matter of personal opinion; he actually encouraged others to give the establishment one-star ratings. This is where I see the value of defamation laws, as they help protect businesses from false accusations and vindictive actions. As a business owner, I would want the ability to shield my enterprise from such malicious behavior too.
I know most people will not agree with me, so go ahead and leave confused or laughing emojis if you feel like it!