In a medium such as Twitter, there is not enough incentive to make users post quality. Morons can post about whatever irrelevant nonsense they want and gain approval from other morons. From inside a filter bubble, PC policing a celebrity can seem incredibly courageous and clever, when in fact it is the opposite. The potential harms of this are real. Richard Dawkins suffered a stroke last week following such an incident, where a random interloper peppered him with a barrage of criticism, taking her gang of followers with her.