Honestly, most of this information can be found through a cursory read of the wikipedia article on the history of Japan - it's not factually incorrect/inaccurate to a fault, but yes it does simplify a lot of issues and systems (as would any video that tries to condense the history of an entire country into nine minutes). So yes, it traded accuracy, information, and depth, all for simplification and convenience. For a summary, it's, as a friend said (paraphrasing here) "several minutes of waffle leading up to the nukes" - take that as you will.