No it isn't. Running an adblocker is exactly instructing my computer to use scissors and cut out the ads from the page. What is the difference in your opinion?

To make it easier to compare, assume I am Trump/Koch wealthy, and I ask my butler Jeeves to cut the ads out of every newspaper I receive. Did I or Jeeves vandalize or violate any law? Now, times have changed, and JeevesBot is a robot rather than a person. Does that qualify as vandalism or violation? And now the newspaper has been replaced with an on-line one, and JeevesBot has been replaced by AdBlockPlus. How is it any different? How is it a strawman?

> Except that such a script is DRM by definition.

The DMCA requires an "effective" DRM. I'm not sure if there is a body of law about what constitutes "effectiveness", but I'd be surprised if "please show this ad" can be considered "an effective DRM.

Furthermore, the DMCA does NOT prohibit me from editing e.g. DVDs - it just prohibits me from distributing those edited copies. And all AdBlockPlus does is edit pages so that they are more to my liking - just as my user CSS does, and as my preselected fonts do.

I think your interpretation of the law is wishful thinking. It's not that DRM/DMCA cannot be, in some form, used to make some forms of ad blocking illegal. I suspect it can. But I am also quite sure that DMCA does not apply to web advertising (and ad blocking) as they are practiced today.