It isn't so much about fault-finding as it is about proper etiquette, which has yet to be firmly established on Facebook. Seeing fault in frivolous, wasteful communication is the basis on which we can establish such proper etiquette. The way in which we utilize the medium can and should be optimized. If someone is going to share something, it should be important enough to be worth sharing. We shouldn't adopt a passive attitude and simply accept the inundation of idle chatter.
"What holds attention determines action." - William James