Equally sides have a legitimate position and it is extremely complicated to consider sides in a situation like this.
Terrible employees fire on their own. They do not stroll up to the manager and say, "I'm fired" (that would be awkward), but they clearly do not meet the criteria they are meant to meet.
On another note, they can only 'clearly' skip these standards if they had been provided obvious expectations to start off with. Consider the circumstance