I wonder whether "Understand me!" would have been an acceptable translation.
Honestly, I doubt it. When there is a translation that preserves the original structure Duolingo usually insists on it. That a different translation could be said in the same situation with a similar effect is not enough.
There is a slight difference: Don't misunderstand feels more forceful, and more blaming than understand, which sound more desperate. That is more connotation than actual definition though, and honestly this sentence could be closer to the later in esperanto