Firing is a Team Decision
Terminating an employee is a significant event in the life cycle of any company. The question is who makes that decision? While the manager of the individual is best suited to measure their performance, it is always helpful to hear the opinions of other members of management who work within an area serviced by this person. Their perspective may help balance things a bit and identify ways to manage the bad performance vs. simply get rid of them. Of course if the sentiment is unanimous then you’ve received validation.