There have been small right wing extremist groups ever since shortly after the Berlin Wall came down. East Berliners moved to the West in huge numbers, hoping to get well paid jobs and profit from the general affluence. But with such large numbers to absorb, there were not enough jobs to go round. The Easterners tended to be far less well educated and so ended up with the poorest paying jobs. This led to a large number of disappointed people, and especially a few, mostly young men, who felt attracted to Nazism, conservatism and the Alt-Right - essentially living in a ignorant dream of past days of glory under the Kaisers and Hitler. They conflated a fusion of Imperialist, Royalist and Nazi ideologies.
For the most part, Germany is one of the most functional and successful democracies in the world. But it is part of the nature of democracies that small aberrations will always be present. Those can be tolerated and managed but only so long as they don't do anything harmful.
