BERLIN — In an effort to counter the growing presence of extremists in combat sports, the World Jewish Congress this weekend launched a pilot program that embodies inclusion in the world of competitive fighting. The event, a joint project of WJC and Vollkontakt , a German group that seeks to counter the extreme right’s grip on combat sports, was held at the Haus des Deutschen Sports, which Adolf Hitler built as part of the complex that hosted the 1936 Olympics. Organizers of the event, “Diversity in Combat Sports,” said they deliberately chose the venue to reclaim sport from the forces...