tl;dr -- the crux of the issue (right or wrong) is making the evaluation information too public. From the news story:

> "[Administrators' primary concern was] making YC [Yale College] course evaluation available to many who are not authorized to view this information,”

> "[Administrators also asked] how they [the site operators] obtained the information, who gave them permission to use it and where the information is hosted."

Edit: Agreed, I don't buy these are the real reasons.