To learn to evaluate past events requires thought processes that don't develop until you are an adult. Kids respond to vivid images and stories, but making history lessons vivid and interesting has been frowned on by the national curriculum thought police.
Then remember, history has been squeezed out of modern school timetabling. By year 9 most kids get one lesson a week at most. Take ten minutes off that for getting in, settling down, winding down and packing to leave, and you'll understand why school-taught history is failing.