This is a history-of-gaming question, and it has to do with the name choice between Barbarian and Berserkers. Due to the race-and-class mixing and matching of many different gaming systems, you can get combinations of barbarians with very non-barbaric races. Examples could include: “High Elf Barbarian” and “Gnome Barbarian.” On the surface, these combinations seem unusual but otherwise OK. It gets worse when you grab a dictionary.
According to Merriam-Webster:
1: of or relating to a land, culture, or people alien and usually believed to be inferior to another land, culture, or people
2: lacking refinement, learning, or artistic or literary culture
1: an ancient Scandinavian warrior frenzied in battle and held to be invulnerable
2: one whose actions are recklessly defiant
If you look at the features of a “barbarian” class, in almost any system, you notice that they align better with the definition of a Berserk (or Berserker). This is reinforced when you read about berserkers in norse sagas. Furthermore, if you look at the linguistic roots of barbarians, it was used to refer to anyone who was not of a particular culture.
Why do we call these classes “Barbarians” instead of “Berserks” or “Berserkers”?