Not going to get into a legal discussion here, but there's more guidance for social web content rules and controls than a few court rulings. If tested, all of the rulings have been in local courts and not run up to the top courts. I also read the site you referenced and it did also indicate, if you get into deeper that the employers rules in the areas where they lost were too broad in scope, and the ruling might/would/could have been different if the policy was tightened up and specified.
That's just the legal side of things. As an employer, and someone who hires and fires, I'm not going to site your facebook page as reason for termination, I'm going to find something else regardless as to where the root information came from. It will be legal, and hold up in court. Also, MD, along with many other states is an "At will" state. There dosen't have to be a reason to release an employee. Doesn't mean an employer can't be sued, but the "at will" portion of the law is already in place.