That's a good argument. However, good adblockers also modify the page (for e.g. some websites don't render at all if the ad is not fetched and displayed, or to

That's a good argument. However, good adblockers also modify the page (for e.g. some websites don't render at all if the ad is not fetched and displayed, or to ensure the webpage shows properly when trackers and advertisements are blocked). We can still argue fair use, as websites can have malwares and we have the right to protect ourselves from it.