Well any type of negativity is usually bad for business. Its why employers fire employees who behave badly or who speak badly against the company. Sometimes criticism is good for a company, a way to improve on product, and how employees are treated.
One thing here on PERB is that any review is a "take it with a grain of salt", whether good or bad, its an opinion of an individual. Some bad threads or replies are MODified or deleted depending on severity; depending on the posted rules.
Individuals usually try to stay away from troublesome individuals or places or websites...