That sounds problematic and is only supported by people mindlessly agreeing to it. I know someone who got jobs at google and apple with no linkedin, and he wasn't particularly young. What do you do in the face of it? I say quit entirely. It was an easy decision because I got nothing out of it during the entire time I was on it.
I have heard people say that LinkedIn was vital to their career.
For myself, I agree with you: one should quit (and I will)