The concept of the “other”

Upon reading the introduction of The Second Sex by Simone de Beauvoir, the concept of the other caught my attention. It would appear that when we “other” (de Beauvoir 6) something, we are essentially distinguishing it. That which is designated as the “other” (de Beauvoir 6) is set apart from what is correct, and often considered a deviation from the norm. Othering has a wide spectrum of severity, and can take many different forms. On the extreme end, it can be anti-semitics looking at Jewish people as sub-human. On the lighter end, it can be natives to a particular country who view foreigners as being strange. I wonder, why do we as humans like to “other” people so much? Why do we always like to set people apart as being odd, strange, deviants, or in the worse cases inferior? There seems to be a theme of always designating a certain demographic to be correct or the best.