The term "grievance" is a term of art in labor and employment law. It applies to situations in which there is a labor union and a collective bargaining agreement that provides for a mechanism with which to dispute a management practice. An arbitrator that is agreed upon by labor and management is selected, and that person settles the dispute. Because grievances are handled this way, there is a fairly quick resolution by an unbiased outsider, which is much better for the workplace than a protracted court battle. Because there is consensus on whom will make the decision, there is a perception of fairness in the result.
Workplaces which do not have this process, those without unions, might have some other dispute resolution process, but these are likely to vary considerably from company to company. However, the same considerations would likely apply, a perception on the part of labor and management that disputes can be resolved quickly and fairly.