We all know who they are.
Perhaps here. :) The rest of the world doesn't know much about them at all. That takes time, and research and most people would rather just have someone they know that they think is intelligent tell them who they should attack. You find this out when you try engaging protestors with actual dialog. They often know very little in terms of reasons why they are there other than some talking points.
When you say 'someone they know' that often comes in the form of heavily biased information from news corporations which should be seen as nothing more than entertainment, people think they have a trusting relationship with their favourite news anchor. Unfortunately the majority of the population get their ideologies and political slants from their TV screen.
Yep. I know. That was part of my point. :)