A boss should never HAVE to yell, but it's his prerogative. An employee should never have to be told twice to report to the boss' office either. If an employee is going to be insubordinate, he or she should NEVER EVER do it publicly, because the boss HAS to make a scene, lest anyone else get ideas.
I know yelling is bad etc. And we don't know the details. We also don't know how regularly chacon disobeyed either. Sometimes when the gig is up the gig is up. if you have been given leash and you abuse it, you have to escalate it. it happens. Wade could have just said "you're done" and left it at that too. But of course you have the union too. Chacon is quite the big man for being as good as he is.