Other obstacles seem gratuitous, even perverse...[T]here seems little excuse for subjecting the reader to 50 pages of verbatim, tiresomely repetitious testimony in one of Oscar’s legal depositions.While I can imagine that a lot of people did find the deposition scene tedious—all they want is blood and gore and her hand unbuttoning his trousers—I am really astounded that the reviewer thought there was "little excuse" for the scene in question.
It's not "one of" Oscar's depositions, it's the only deposition in the novel. It happens early on: the two lawyers in the scene appear for the first time, in their only scene together, and the whole remainder of the plot refers back to this encounter as the reader learns new things about each of them. And it's not the testimony that's repetitious, but the lawyers' constant objections and rebuttals, which take on a Laurel and Hardy type quality.
In any case, I think the deposition scene is literally essential to the novel.