I could think from the point of view of children who are brainwashed and lead to believe things from the ideology of their dictators. JoJo's perception potrays an exemplary embodiment of how these little guys(children) have so many notions and stories that they see and hear around them to learn and believe and build their own ideology at some point of time. With respect to which, their entire lives are going to revolve. They cannot be sure owing to their innocence who is telling a truth and who isn't. Some are just lucky enough to have knowledge of the stories on both sides like that of Hitler and the Jews and choose wisely while others end up carrying the same false believes for the rest of their lives inevitably and base their lives accordingly. The humour in the movie saves from moments when the exaggerated terror and propoganda of the war completely drowns us.
When I commenced watching the movie and saw scenes of Hitler and preparations for war like situations I started expecting to deal with seeing a lot of action, drama and too much anguish associated with it. But this movie potrayed the entire situation in a more humourous yet distressing manner which made it worthy enough to watch. To sum up it all, it was thought provoking yet not too disturbing considering the depiction of optimism in even the most dreadful scenes.