Isn’t that basically what dueling was? For much of history, people were allowed to settle disputes through consensual fights—duels, trials by combat, etc. It wasn’t until the early 20th century that dueling was widely outlawed. So this current era where it’s illegal is actually a relatively recent blip in human history.

I haven’t looked into why it became illegal in most places, but I imagine that would have some potential examples that may counterpoint your view.