It is not at all clear that Dr. Seuss wants the United States to do anything specific in this cartoon. The US response to the abuse of Jews is not the point of the cartoon. Instead, the cartoon is really just a criticism of Hitler and the government of “Vichy France.”
In the cartoon, Dr. Seuss is simply criticizing the brutality of the policies of Hitler and Pierre Laval. Pierre Laval was a major leader of the part of France that stayed nominally independent after Germany conquered the rest of the country. Laval helped carry out Hitler’s anti-Jewish policies. In the cartoon, Dr. Seuss is simply pointing out that these policies are brutal. He is using part of the Joyce Kilmer poem “Trees,” which is about the beauty of nature. He is implying that Hitler and Laval are perverting the natural way of things with their anti-Jewish policies.
Dr. Seuss does not call for the US to do anything specific in this cartoon. He does not call for anyone to do anything. Instead, he is simply criticizing what is being done to the Jews. We can infer that he would want someone to do something about it, but he is not actually coming out and saying so.