This is going to be easily overturned. The ad blockers use the dns service and that is not part of what copyright protects. Modifying the results of dns requests is not protected by the copyright law itself. The argument could be made that giving "false" or "changed results" could be modifying the websites programming but you can't have it both ways, saying that your use of a free and public service is part of your copyright rights is surely drawing a long bow. It could be managed by implementing dns on the website (encrypted) to prevent normal dns from being used and hence blocked