Axel Springer has fighting Eyoe over the adblock they have made a fortune with. What Eyoe has done has undermined the fabric of the ad supported internet.
Now the fight is moving to copyright where the accusation is that adblocking is modifying the copyrighted HTML document.
The legal point is whether the host which is copyright extends to the user who then modifies it. That makes the modification a derivative of the copyrighted work and therefore it is infringement.
The same applies to a book, the printer makes copies to consumers. The book in the consumer hand is still copyrighted.
Given the wilful use of adblocking, the penalties under Canadian law are rather strict. Commercial copyright infringement is $20,000 per work and noncommercial infringement is $5,000 per work.
The German legal system is under increased scrutiny and over time we are following the case law as it works it way through the courts.