While the Westboro Baptist Church seems to be the most common target for universal Facebook anger, there are a number of things that upset people to the point that they need to tell everyone just how upset they are. What value is there in posting that you feel the same way everyone else does about something? We're not sure. We are sure that as long as there is Facebook, people will continue to post sentiments that are pretty much universally agreed upon, such as that the Kardashians annoying and school shootings are tragic.
For how much we all want to be individually unique, sometimes we just want to let the world know that we feel the same way everybody else does.