Answer and Explanation:
Vonnegut's letter and 1984 are showing how the hiding of messages and concepts is done by people who are in power to manipulate, alienate and limit people's access to information that will make them reason.
These two works show how the reasoning of the mass, of the people is dangerous for the powerful and for that reason, they will try their best to deny any type of media that encourages racism at the expense of alienation. This occurs through the censorship of books, the denial of historical facts and the positioning as a figure that contains the truth and that must be followed. This occurs through manipulation.
However, even in the midst of these similarities, these two works present some differences, mainly regarding the level of power of the active manipulative force. In Vonnegut's letter, this force has a more domestic power and is limited to a region, which shows that the capacity for manipulation may be closer to what we imagine and it is necessary to perceive and fight it. In 1984, the manipulative force is something comprehensive, governmental and greater, which has the power to interfere in absolutely any factor and any element of human knowledge.