But when you use your Employers name and/or business Twitter, You and your employer can take the heat for you. Because at that point no matter what say, you are representing your employer. Many employees have been fired simply for social media posts, not even posting on a professional social media or representing themselves and their company in a professional manner. But just for having the employed at information filled out on a social media page.
One of former companies, said anything you post on any social media personal or not, can be considered conduct by an employee, even if they do not list themselves as an employee of the company.
Freedom of speech is one thing, but freedom of employment is another.
Freedom of speech says the "government" can not infringe on your rights, it says nothing about your employer (unless you work for said government). And beyond that, freedom of speech does not mean they have to employ you, they can say you are free to say anything you want, but if you say that you will not work here.
He is a media person. His job partially is public relations. No matter what his Twitter says he does represent the company. Any heat he takes can and should directly affect him and the company he represents. Media is supposed to be unbiased, regardless of the source. I agree he can and should cheer for whatever team he wants, but posting that kind of derogatory posts on a business social account is stupid, and probably should happen on a private social media if at all when you are a public figure, no matter how small time, especially when it directly targets 50% or more of your audience.
Our media top to bottom is awful and its time people start holding them accountable.