In Germany, this is defined in ยง 95a UrhG [0], as in "bypassing safeguard measures to gain access to copyright material". "Anti-Anti-Adblocks", as in Adblock filters bypassing adblock popups, were already declared illegal in the BILD case [1].
Whether or not clearing cookies would count as bypassing is an interesting question, because Adblockers themselves are legal. The specific BILD case is about blocking and disabling a tool to detect adblockers, in which case it fully denies access to the article.
Ie, the anti-anti-adblock is actively interfering with the site's function on the client side.
Cookies and referer are handled on the server-side and outside the user's control.
I would question if the last sentences of 95a apply to setting a referer and clearing cookies. They are more closer to tampering with computer system (263a).
Yes, that's why I've added the second link. Someone posted a tutorial on how to bypass the BILD Anti-Adblock. He argued that this is not an "effective" protection, but a court ruled an "Anti-Adblock" script as "effective".
It depends on the court. IIRC, that ruling came from the Landgericht Hamburg, which has become a bit of a running gag because of their copyright friendly rulings.
The effectiveness of the access control is usually a factor.
If there is just a banner hovering over the actual text, and the extension merely removes that banner, than one could question whether there even was an access control in the first place.
As an extreme example, a Finnish court ruled that CSS (as used by DVDs a long time ago) was ineffective.
[0] https://dejure.org/gesetze/UrhG/95a.html
[1] https://www.wbs-law.de/it-recht/verbreitung-einer-anleitung-...