A member of BTS wore T-Shirt printed Atomic Bomb. I’m sad to imagine victims in Hiroshima and Nagasaki. So do most of Japanese. If they want to show their patriotism for South Korea, they should become soldiers to defend their own country and people, not to sing and dance in Japan.
Moreover, they must be supporters for Nazis. Wearing SS uniforms in Europe, they must be excluded. In Japan they also be. In South Korea, however, they certainly are welcomed!
Do you want to maintain a friendship with such a people?