Maybe that theory is correct. But I feel like pretending this post is getting to the top of HN because it's a technically interesting diagnostic analysis is sort of silly.
It can take a lot of time and effort to develop instincts like “scrollbar jumping and network calls are related”. They’re so obvious to me that I didn’t even bother inspecting anything, I just “debugged” on my phone by connecting familiar dots and describing the familiarity. But if it’s not immediately obvious to you and if you have an inclination to be more familiar, I’d strongly recommend spending more time manually fuzzing rando sites with dev tools open. You’ll probably get a lot more out of that than dissecting personal motivations on any thread on any site. And you’ll have a much better calibrated bullshit detector too.