I feel what you’re saying is an exaggeration. In highschool history class we definitely had conflicting viewpoints on the causes and blame for WW1, varying perspectives on the use of gas in warfare, the arguments about the ethics of bombing civilian targets in WW2, and the debates about the necessity and ethics of the conflicts between “western” and communist powers during the Cold War. This hardly unleashed “chaos” - it was an above average but otherwise normal Canadian highschool history class.