Reading is indeed a pleasure, though a difficult one. And yet the word "pleasure" is completely inadequate to describe the experience of reading literature of the Holocaust. It strikes me as an awkward word to describe an encounter with literature about pogroms, ghettos, concentration camps, and death camps (it would also strike me as bizarre to suggest to writers and readers of Holocaust literature that the content of this literature doesn't matter).
Why, then, would we read Holocaust literature? Perhaps for the same reason many survivors write about the Holocaust: to witness. In the Holocaust literature I've encountered, survivors and others make little attempt to find meaning in the Holocaust. Often the works rather document, witness, pass on. A book like Charlotte Delbo's Auschwitz and After and the books of Primo Levi can provide the inner experience of a Holocaust victim and survivor. As a reader, I cannot encounter these works for pleasure and it would be blind to encounter them for no reason but to examine their artistry. But in reading them, perhaps I am participating in the effort to bear witness, to remember.