The employer-employee relationship in the US is generally "at-will", which means either side has the right to end the relationship for any time and for basicall

The employer-employee relationship in the US is generally "at-will", which means either side has the right to end the relationship for any time and for basically any reason. But the actual reason why these people are getting fired is because employers are scared shitless of these digital lynch mobs. To them, _not_ immediately firing a person who makes an offensive joke means the employer tacitly approves of the employee's behavior and thus the _employer_ becomes a target.