> One cannot be DDOSed with junk when not actively trying to stuff as much junk into ones head.

The junk gets thrown at you in mass volume at low cost without your permission.

Let's say a relative of yours who isn't too tech literate is using a search engine to lookup some information, could be presidential election, COVID, some news story. If one of the results on the first page deviate from others, it's easy to notice. But if all of them agree, they became the truth. Of course your first thought is to say search engines are shit or whatever off-hand remarks. But this example is just to illustrate how the volume alone can change things.

The medium doesn't matter, these things could come in many forms, book reviews, posts on social media, ads, false product description on amazon, the problem is the volume.

Of course, these things exist today but the scale is different, just like the difference between firearms and drones or weapon of mass destruction. If you think that it's the same old game and you can defend against the new threat using your old arsenal (in this example: infantry against drones), I admire your confidence but you're in for a surprise.