It's partly a flex but I think it's a common experience. There are lots of things that the kinds of people who are on this site - for the most part, intelligent people - will pick up on subconsciously.

When we realize it's not common knowledge, we get excited and/or become proud of ourselves, and explain what we think to indulge ourselves (because we were just given evidence that the knowledge isn't as common as we thought).

I think the first part of gp is common knowledge too, but his conclusion is novel.

It is pretty common to explain sleep as when your mind cleans up and store stuff in long term memory. From there it is largely a point of view distinction between “keeping stuff you want to save” and “throwing away stuff you don’t want to save”

I clearly remember having read years ago that sleep is about forgetting/discarding unimportant memories and consolidating memories. It's not flexing, but the general thrust (not the specifics) is common knowledge to pop science readers.

I haven't noticed that.