WASHINGTON-The protests over China’s human rights abuses as it prepares to host this summer’s Olympics underline a key fact: Sports and politics are supposed to remain separate, but rarely are. A new exhibit at the U.S. Holocaust Memorial Museum outlines another stark example of when athletes become ambassadors: the 1936 Berlin Olympics, used by the Nazis as international propaganda to trumpet the strength, nobility and supposed “superiority” of the German people. The exhibit follows Germany as it tries to regain stature after its withering defeat in World War I. Germany won the 1936 Olympic bid in 1931, two years before Hitler came to power. But international debate on whether countries should boycott the games grew heated as Germany banned Jews and Gypsies from its teams, and racism and anti-Semitism in the country increased.