From what I have read the guy was not fired for heckling on the golf course nor for his behavior while attending the tournament.
. He was fired for his subsequent behaviour on social media using an account that clearly drew attention to his job title ,position and employer. . As such he continued on as an azz while on Twitter while using an account that was identifiable with his position and place of employment , in essence representing his place of work. As such he was, correctly fired.
most all companies now have social media policies and this guy is either incredibly stupid or an azzhole, likely both.