Why would anyone, ever, think that me not looking at their ad should be illegal?
It goes a lot deeper than that. I am running software on a device I own. That software requests a resource from a remote service. After receiving it, the same software manipulates that resource in ways I have specifically asked it to in order to meet my needs.
The plaintiff's case is that they have a legal right to tell me how to view a resource once it's on a machine I own. Copyright etc. isn't involved; I'm consuming a properly licensed copy of the resource that they sent to me. I'm not distributing it, either in original or modified form.
There are already a million other ways I might modify that content today. I can apply my own CSS so that font sizes and contrast are to my liking. My web browser may actually be a speech synthesizer or braille reader. I may be viewing it on a mobile device that simply can't render it in its original form. But according to the plaintiffs, none of that matters: either I view it as originally intended or not at all.
If they're going to assert insane things like that, I suggest they form a W3C working group to publicize a standard way of describing what uses are acceptable for that content. Then my web browser could parse it, see "ADS_MAY_BE_REMOVED: FALSE", and give me a popup saying "This page is published by sociopaths. Continue?".