What is the problem with learning history from only one perspective?

History is a thematic analysis of certain events while excluding others. When history is only seen from one perspective it excludes actual writings and positions from individuals who differ from this pre-established perspective. For example, in the United States when they discuss the Cold War and its "flare ups" across the third world, they rarely analyze the trauma they inflicted on those countries (like Vietnam, Angola, Iran, Nicaragua, Chile, etc.) and see the war as a proxy contest between the United States and Soviet Union. Or, there is a consistent belief that the United States defeated the Nazis, which fails to take into account that the Soviets bore the brunt of the Nazi military forces and drove the Nazis out of Eastern Europe without Allied military assistance while over 30 different national armies (led by the US and UK) won the Western and Southern fronts which were more lightly defended.

These views of history fail to take into account perspectives which clash with the dominant pre-established perspective and this is why they are problematic. They prevent all of the facts from being properly weighed and assessed.