Instead of right and left wing “extremists”, maybe they are Germans that just want to keep their culture and country.
Unfortunately, the German government disagrees with them. It appears as though they are more interested in PC, than in national security. Maybe it's a white guilt problem.
Perhaps that's true somewhat for the right-wingers.
But the left-wingers have the expressed aim of destroying German identity and culture (their slogans are "Nie wieder Deutschland!" - Never again Germany! - and "Deutschland verrecke!" - Croak, Germany!). Support of illegal mass immigration is one of their tools. And they outnumber the right-wingers by a large margin. They are today's SA.