As punishment

In some situations, people's hair is shaved as a punishment. Before World War II, the Nazis would cut off the beards of Jews as a prelude to other forms of abuse.

After World War II, head-shaving was a common punishment in France, The Netherlands, and Norway for women who had collaborated with the Nazis during the occupation, and, in particular, for women who had "collaborated" sexually. [7]

In the United States, during the Vietnam War, conservative students would sometimes attack student radicals or "hippies" by shaving beards or cutting long hair. One notorious incident occurred at Stanford University, when unruly fraternity members grabbed Resistance founder (and student-body president) David Harris, cut off his long hair, and shaved his beard.

In Arab countries, shaving off head-hair is sometimes used to shame and humiliate male prisoners.

During the witch-hunts the alleged witches were stripped naked and their entire body was shaved to discover the so-called witches' marks. The discovery of witches' marks was then used as evidence in trials[8].

In North American residential and industrial schools head-shaving and short haircuts were given to the Indigenous children on entry into the schools to force them to adopt the Western tradition. Head-shaving was also a form of punishment for the Indigenous students of the schools, and was particularly traumatizing as many Indigenous cultures place a social, cultural, and/or religious importance on hair.

wikipedia.org