An official explanation from a Brandeis spokesman:
The decision to take down the Palestinian picture exhibit has been seriously misunderstood and mistakenly characterized as censorship. Brandeis encourages serious discussion of all issues, including many that are sensitive, controversial or even painful. For that very reason, the University pays careful attention to the time, place and manner in which exhibits, debates, talks, etc. occur. The concern is heightened when public space at the University is being used.
In this case, a grouping of Palestinian drawings was hung recently in the Goldfarb library. The drawings were part of a Brandeis student's class project. The student described the installation as a way to "bring into the Brandeis community a different narrative about the Palestinian-Israeli conflict."
The timing (in this case, immediately before final examinations) and physical location of an exhibit often require as much dialogue and discussion before being undertaken as the exhibit itself. In the absence of any larger educational context, various administrators received reports that some students found the exhibit confusing and upsetting.
Out of concern for the community, the University elected to take down the pictures at this time. In this case, as in any other, it would be our hope that interested faculty and students would come together to create an exhibit or event that would allow for thoughtful discussion around the points that the student had hoped to communicate.
The first three paragraphs quoted above actually make a certain amount of sense: whoever decided to allow an obviously extremely controversial art exhibit to be displayed in the library during finals time was guilty of poor judgment. During finals, especially at Brandeis, (which, at least when I went there, was reputed to have the third-hardest-working students in the country, after Cornell and Hopkins) students are focusing on their studies, and it's just dumb to choose that particular time and place to display a provocative, political, display of art.
However, the final paragraph more or less ruins this point, because it reiterates the position Brandeis previously took, which is that this was not simply a "time, place, and manner" restriction (to borrow phraseology from constitutional law), but also a content-based restriction, and that the display would have been fine if it had been "balanced" or on some other controversial topic perhaps less likely to raise hackles at Brandeis.
In short, it makes sense for the library director, or whoever is in charge, to have a policy, "the library is off-limits to controversial political displays around finals time," and for that individual to be overruled if he doesn't enforce such a policy. However, the Brandeis administration is waffling between that relatively cogent rationale, and one that focuses on "lack of balance" and the facts that some students were "upset," neither of which is a justifiable reason to take down a previously approved exhibit. Brandeis would have been on much more solid ground if it had simply announced that the exhibitor was welcome to display the art at any time and in any place on campus, except during finals to a captive audience in the library.