Not sharing ideas is a fear-driven activity.
The fear being: I will look bad if I share an idea that other people do not like.
This is what keep people from promoting their friend's music/art/resume/business until said friend's music/art/resume/business has already gained some popularity.
This is exactly how Facebook generates it's non-sequential news-feed. Your post does not see any engagement until someone comments on it. Only then do their friends see it and so on. Quite the chicken and the egg.
So when you share that article from your feed and post it on your wall, you saw it on your feed because it was popular in the first place.
But we like it this way. This way where the curation is someone else's problem.
Preferably an algorithm's problem.
Please, just don't make us do the work.
We are busy.
This post is inspired by my friend who recently tried to quit Facebook and was faced with emotional sleight-of-hand to make him stay. He talks about his account on his podcast. You should subscribe, he is really good at it.