I think the bigger issue is why FB hasn't been able to create the kind of conversations that reddit does- the lack of real threading and the lack of a true downvote (preferably anonymous) keep conversations on FB abysmally superficial. You can't engage in a debate with someone if the back-and-forth gets impossible to follow after the second reply, especially with more than two participants. Likewise, FB and users have no idea whether people disagree with a post or are simply ignoring it; or on something like a critical article, whether a user agrees with an article and it's the article's subject which makes them angry or the user disagrees with the article and the post itself makes them angry. FB, with its status as the defacto social network could be a place where people have real constructive discussions, but instead its inability to foster real dialogue has a lot to do with the current stupidity of political discourse and the problems with reality bubbles and whatnot.