Leaving negative review = potential lawsuit?

WT
I was shopping for home insurance through an insurance provider and I noticed that one of the things covered under their umbrella policies was "lawsuits over filing a negative reviews online" 😳 wtf? That's a thing? I chatted with the insurance rep online to ask if that was something that happens often and was told "more and more, more then you think" 
How do you feel about that?
 To me it defeats the purpose of "consumer beware" reviews some people rely on before going with a company for a big purchase, leasing an apartment, hospital experience, etc. to me it's not an honest reflection of a company if negative reviews are removed. 
Or
If you're a business owner can you offer some insight defending this? I just don't think it's fair for someone to have to second guess their 1 star review they wrote online in fear of being sued or fined or written some ugly notice demanding it be deleted.