Facebook already exercises a lot of discretion -- they reorder posts on your timeline to drive engagement, they promote related links, they have the Trending bar, etc. People aren't asking them to do more. They're asking them to do what they're doing now more responsibly.
I couldn't agree more. I don't think Facebook should necessarily block fake news (however you want to define it) but it might be nice to let me know before I share a story that they think it's satirical because of reason A and reason B or that it's inaccurate for other reasons.
This is good for me because I don't look dumb for sharing something that's incorrect and it's good for Facebook because now they know even more about me (that I love satire but hate fake news, for example).