Thanks for the perspective. Yea you're right, I think different platforms have different effects on people. As an example quitting TV shows was difficult for me, whereas most people I've talked to don't even think of TV shows as a necessary bad thing.
On HN/LI, at least for me I really don't find them disruptive or time sinks. LinkedIn seems boring, HN doesn't have infinite scroll, and again most articles don't really interest me that much.
I don't use Reddit exactly because I feel the posts evoke an emotional response from me and I tend to stay there. Haven't used it in a long time, same with other infinite popular scrollers.
Anyway, my core point being for the platforms that do trouble me in my experience going all-out helped. If I set a time limit or time window or use grayscale or all those hacks it doesn't work. All those are more like gateway drugs. So if HN/LI does truly provide more noise than signal I would personally cut it out but that's not the case for me at the moment.