>First, AdBlock Plus (ABP), the most popular ad blocking software, has its roots in Cologne. Second, a cultural factor: German opposition to online advertising that manifests itself in the government’s obsessive anti-Google stance pushed by large media conglomerates such as Axel Springer SE.

Those are pretty long shots. I would rather say that the historical effect of Webwashers popularity is more powerful than any of the both reasons above.