Final answer:
Males are not allowed to wear hairpieces or wigs in the military as it goes against the established rule of having short hair. The purpose of this rule is to promote uniformity and remove individual identity markers.
Step-by-step explanation:
According to the information provided, males are usually required to have short hair when entering the military. This means that wearing hairpieces or wigs would not be allowed as they would not resemble natural hair. The purpose of this rule is to enforce uniformity and remove any markers of individual identity, allowing soldiers to be resocialized into a common identity as a 'soldier'.