Create two restaurants with the same exact look, menu, appliances and prep but different names and Yelp/Google entities. Enter bad reviews in one, and see what happens. That's how we would be able to tell if its the reviews or the restaurant that hurt the restaurant.

An aside: With this mesh of human and company rights [whether or not you agree], does a company -- like people + GDPR -- have the right to be forgotten, or not exist somewhere they wish not to?