They were trying to make the argument that they html was copyright and thus modifying and redistributing it (IE removing the ads) without license was infringing. The entirety of the consideration was whether programmatically removing ads in the page before serving it to the user consisted of redistribution or reproduction.
Definitely a stretch attempt at interpretation but not surprising and not at all unreasonable.
Your analogy isn't fully sane - You bought the book you're scribbling in, and have the right to deface that copy as you please, and even resell that copy. You may not reprint it with a word whited out and offer it for reproduction or distribution as your own.
This side of copyright law is very well established and not ambiguous.
Definitely a stretch attempt at interpretation but not surprising and not at all unreasonable.
Your analogy isn't fully sane - You bought the book you're scribbling in, and have the right to deface that copy as you please, and even resell that copy. You may not reprint it with a word whited out and offer it for reproduction or distribution as your own.
This side of copyright law is very well established and not ambiguous.