The World War II poster you shared, or will share at least, displays propaganda instilled by the United States and controversial themes to make the Germans seem evil. The poster you shared with the question, that you shared it right? Is it coming up soon? Well, the poster shows the negative consequences of what would happen if fascism overtook the United States. It used fear to instill a feeling that the Germans would take over the United States and used this to generate hysteria.
Now, with hysteria, you should note that this is a psychological effect. Propaganda is very effective. Most people believe that if they lived in Germany, they would have stood up for the Jews. This sadly is not true in most cases. Propaganda, as well as the nationality in a country, can change one's belief so much that they become blinded by the belief itself and are naive to even understanding that they were fooled into hating a group of people for no reason.