I've known about the Koch brothers, Charles and David, for decades. The billionaire owners of Koch Industries have for years publicly supported free-market think tanks and liberty-oriented causes. Until recently, such civic engagement was considered patriotic.
But as George Orwell so brilliantly illustrated in 1984, hatred against some other is an invaluable tool for an authoritarian regime to control the masses. 1984's bogeyman was Emmanuel Goldstein, a traitor possibly invented by the regime, a face toward which the enslaved populace could direct their anger.
Ask any leftist you know these days about the "Koch brothers," and you're likely to provoke a look of disgust. Leftist political organizations and their acolytes in the media have turned "Koch brothers" into a dirty word, along with "Citizens United" and "corporation."
Watch MSNBC personality Rachel Maddow completely make up an entire news segment claiming the Koch brothers were behind a push to drug-test welfare recipients, an issue the Kochs had absolutely nothing to do with.