I suppose it depends on the prevailing culture (I'm guessing American). As a European, I would say firing someone over the above would be a deeply intolerant act, and possibly illegal.
In a lot of cases (at least in the UK), it could fall under gross misconduct, for which your employer is allowed to terminate you on the spot. Of course, you can then take them to an employment tribunal who will then deliberate on if this was appropriate.
