Often people don't agree even on the most basic facts. For example, in the case of the Polish-Soviet war (1919-1920), "who attacked who?" is still a controversial topic.
Valid point. But why delineate differences of opinion across language lines when there are all sorts of reasons to disagree. Whether the disagreement is political, philosophical, regional, cultural, seems like using language as the key differentiator is a fuzzy proxy. You need to find a way to resolve these differences if the content is going to be trustworthy.
There is no way to reconcile those histories.