Thank you Sean for talking about this in such a clear and lucid manner. I'm glad someone with your reach on the internet spoke about this.
LinkedIn is a great platform for professionals to connect and discuss about their professionals. But like you said it has become a cesspool of everything else, be it motivational quotes, inspirational stories, fake inspirational stories, birthday celebrations, jokes or puzzles!
I have uninstalled LinkedIn and probably won't visit it except to update my profile.