The problem with your argument though is that the amount of "junkiness" (if we're going with the food analogy) is directly equivalent to how well you curate your experience.

If your Facebook friends are people who share useful and enriching content and make insightful comments, for instance. Nobody's going to argue that the default front page of Reddit is anything but junk, but imagine you've unsubscribed all of those and now follow things like r/programming and r/books - you are getting more useful content.

Basically I take issue with denigrating all of social media as some kind of crap. It's precisely as crap as the person using it wants/allows it to be.