I think this dismissal really ignores a very crucial difference. Unlike magazines or even TV for that matter, the new social media has personalized and detailed information on individuals and can tailor their content and design to target every person individually.
IMO, that is a substantial and qualitative difference that makes the new “distraction” mediums far more effective and dangerous.
One other problem is, magazines end. They have X articles, of which you find Y interesting enough to read, and then that's that. You read it. It's done. You go do something else.
Digital feeds never end. There's always something new, always something interesting. There's always something. You can keep staring at the screen endlessly. And if one app doesn't give new stuff anymore, there's 10 other apps within a tap away to give you more.
Yeah, having lived in the world before the Web had much on it, when it was slow and inconvenient to use, and could only be used certain places (at a desk, with a computer), when a computer not connected to the Internet wasn't a useless paperweight, and then in the world after Facebook and the iPhone and the full blossoming of the spyvertising industry, web-connected cell phones and the modern attention economy are strikingly different. There's no comparison to books or magazines, however low-value, or even to TV or radio. It's a whole other thing, and overall mostly terrible.
IMO, that is a substantial and qualitative difference that makes the new “distraction” mediums far more effective and dangerous.