Thank you for the opportunity to help you with your question!
Yes the First World War contributed hugely to the erosion of the value of heroism. Each side picked heroes according to gains the individuals brought towards their cause rather than genuine heroism towards all of humanity. Actions that would have otherwise been termed as war crimes at times earned someone a hero's medal. While it certainly wasn't the first conflict to do so, it's global nature made it large scale and set the template for further erosion of the value of genuine heroism.
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