I've been using Facebook for years, awesome tool, I'm in contact with friends, relatives and parters, it is awesome.
However, HN downvotes do seem to be trending toward "I disagree" recently too, in my experience.
By all means, if you can't use a website without becoming addicted to it, disconnect.
But there's no need to damn everyone else with the "that's exactly what an addict would say" kafkatrap rhetoric that seems to be so popular every time the topic comes up.
I use FB to keep in touch with family and friends, and as a way for them to invite me to events. I avoid the "news" feed like the plague, and strongly prefer Imgur's User Submitted for a feed of "what's going on in the world today".