Why does the director of Path of Glory show the aspect of World War 1

according to howard zinn, the history presents the encounter between columbus and the arawaks as a heroic adventure of descovery but leaves in the shades the cruel slavery and bloodshed columbus led in order to pay back to his investors. he sent the indians back to his nation as a payment, slaved them to find gold in the land and punished them when they didn't find any. history presents columbus as a heroe and even celebrates his day, when in reality he led a genocide. zinn describes the story of the colonization from the arawaks point of view.