The employee made two fatal mistakes. 1. Posting comments on the company social media site. She should have been fired straightaway. 2. Allowing her employer access to her social media site. She should have quit, and if the basis for firing was a comment on a personal web page with no connection to the business, she should have sued the employer.
Both of these people should not be in business, they don't have a clue.
If the employee’s comments were on a site like FR, and thus not linked to the employer’s site, does the employer then lose all grounds to monitor and fire?