most DUers are familiar, at least somewhat, of the history between the creation of an atmosphere of hatred and some of the tragic assassinations in the 1960s. Recognizing the relationship between those who stir the pot of hatred and fear, and of those murders, does not in and of itself mean that a person believes in conspiracy theories. If indeed there are "lone nuts" out there, it would seem likely that being exposed to frequent rants aimed at a specific target could have an influence upon their sick thinking.
The most famous instance, I suspect, would be the "wanted for treason" ad that was published in a Dallas, Texas newspaper when President Kennedy was scheduled to visit. A similar theme would be found in a cartoon published in the Nation of Islam's newspaper, that appeared to call for the beheading of Malcolm X
Not all of that era's appeals to what Robert Kennedy called "the darker impulses of human nature" were found in pieces aimed at the angriest people in society. Indeed, three months before JFK was killed, author Victor Lasky's book, "JFK: The Man and the Myth" was published. It was, to the best of my knowledge, the first time that an author connected to the intelligence community published a book attacking a sitting US President -- claiming that Kennedy was a socialist, intent upon forcing a dangerous system of government (and business) upon an unsuspecting public.
After Dallas, the book was "pulled" for two years, because the publishers believed it might be considered connected, in some way, to the assassination. If nothing else, I think, it's fair to say that the book's analysis of JFK was the type of decaying shit that could fertilize the paranoid fantasies of the rabid right wing.
Still, in my life-time, the quantity and quality of hateful, paranoid lies spread in the media, and on the internet, about President Obama reaches an all-time low. While I am a firm believer in Amendment 1 -- and in no way am suggesting the government should dictate what can or cannot be printed -- I strongly urge people to contact the sponsors of those media that promote such vicious crap.