> If you cannot communicate with a beginner in language they understand, A.) you don't really understand it either

This is true, but the problem is that people will always prefer the explanation that is, as the saying goes, "simple, neat, and wrong" over the explanation that is more complicated, especially if they (and possibly the person explaining) aren't aware that the simplified version is wrong. Even if one starts from an accessible viewpoint, any concept that is worth isolating as a concept will involve some difficult step in its exposition, and it is at that step that the person seeking to understand—not the explainer—has to decide whether to stick with the explanation despite the difficulty, or to be satisfied with an easy and wrong explanation.