Look, Glassdoor is complete bullshit. It's unbelievably biased against companies and the CEOs. Basically, the simplest way for an unhappy employee is to write a stupid review to Glassdoor. I used to work in a company which didn't suite everyone and the Glassdoor reviews were brutal. The HR tried to adress these issue and encouraged people to talk with their managers and with HR if they had issues. None of my coworkers ever did that, they just wrote a Glassdoor review and never bothered to talk it out with the managers.

The company was receiving calls on daily basis from Glassdoor and their affiliates offering to remove the negative reviews for thousands of dollars. If somthing, this is at least unethical business practice.