This is the core problem with slacktivism: in addition to being a lazy and pointless alternative to actually doing anything, it breeds a weird combination of zeal, self-aggrandisement and superficiality. Slacktivists get all worked up over out-of-context pictures (which often turn out to be manipulated or misrepresented) and try to sum up very complex issues for others (that they often barely understand themselves) in 10 word sound bytes. No wonder they're left with egg on their faces in situations like this.