Classic. Just...classic. From Unredacted--great blog of the National Security Archive--the CIA argues that release of the last volume of its internal history of the Bay of Pigs would "confuse" people and so it should remain secret.
The idea that scholars would come to "erroneous" conclusions is hardly an argument at all. Historians and political scientists disagree on just about everything, and more primary documents will more likely lead to useful debate rather than some unified view the CIA would consider "distorted." Further, given how much debate there still is about the Bay of Pigs, it is hard to imagine what kind of bombshell remains that would alter that debate very much.
Either way, it's insulting. The public has a right to know (and even a right to be confused!). Even if the CIA historians are discredited for this case, then that is an important part of history as well.