Someone here not long ago on HN opened my eyes to the 'lists' feature of Twitter, it's been a remarkable improvement for me with the platform. "IRL" friends in one list, "Net" friends in another, sports commentary (because that's a thing I'm into), etc. etc. Crap is more or less 'siloed'.
I wish twitter promoted the feature more, to be honest, I think it can help with some of the gripes you have, if not for you maybe for others as it did with my experience on the platform.
Incidentally, the iOS Twitter client also shows tweets in your feed which your followers liked. And you can't turn that off. I don't understand that feature at all and it made me switch to a third-party client.
People could post the same stuff on FB, Twitter, or email lists the hard part is finding stuff worth subscribing to. It’s really more about what platform creators use, and Twitter’s lightweight nature means a lot of interesting things end up on it.
I follow friend and family on facebook. If they post crap, it's because they have stupid things to say. I don't have many friends who I think are stupid.
Obviously you can follow celebrities on facebook and only follow friends on twitter but it doesn't feel like they're made for that use case, the 'reverse' of what I use it for.