30 years later, Asheim took another look at censorship–you might also be interested in this one:
Asheim, L. (1983). Selection and censorship: a reappraisal.Wilson Library Bulletin; 58 (3) Nov 83.

I knew there must be some history to this. The Asheim essay is exactly what I was looking for. Thank you.

Here are some long, but worthwhile quotes:

“If we are agreed that the standards employed as touchstones by the librarians are essentially the same as those used by the censor, the distinction between selection and censorship will have to be found in the way the standards are applied. The honorable surgeon and the sadist both wield a knife, but in the framework in which they perform their operations and the premises on which they base their actions lies the key to the distinction between them.”

“The major characteristic which makes for the all-important difference seems to me to be this: that the selector’s approach is positive, while that of the censor is negative. This is more than a verbal quibble; it transforms the entire act and the steps included in it. For to the selector, the important thing is to find reasons to keep the book. Given such a guiding principle, the selector looks for values, for strengths, for virtues which will over shadow minor objections. For the censor, on the other hand, the important thing is to find reasons to reject the book; his guiding principle leads him to seek out the objectionable features, the weaknesses, the possibilities for misinterpretation. The positive selector asks what the reaction of a rational intelligent adult would be to the content of the work; the censor fears for the results on the weak, the warped, and the irrational. The selector says, if there is anything good in this book let us try to keep it; the censor says, if there is anything bad in this book, let us reject it. And since there is seldom a flawless work in any form, the censor’s approach can destroy much that is worth saving.”