Why when two people share the cost of a date do we say they’re “going Dutch”?

War has influenced the slurs in our language more than anything else. For example, when a soldier runs from battle the French say he’s gone travelling “English style,” while the English say he’s on “French leave.” During the Anglo-Dutch wars of the seventeenth century, British insults were that “Dutch courage” came from a bottle while a “Dutch treat” meant that everyone paid their own way, which of course was no treat at all.