This is a bad summary of Dennett’s view, or at least a misleading one. He thinks that ‘qualia’ as most philosophers of mind define the term doesn’t refer to anything, and is just a weasel word obscuring that we really don’t have much of an understanding of how brains do the things they do. Qualia get glossed as the “what-it’s-like-ness” of experiences (e.g. the particular feeling of seeing the color blue), which isn’t wrong, but is only part of the story. ‘Qualia’ is a technical term in the philosophy of mind literature, and has a lot of properties attached to it (privacy, incorrigibility, ineffability, so on). Dennett argues that qualia in that sense–the philosopher’s qualia–is incoherent and internally inconsistent for a variety of reasons. This sometimes gets misrepresented as “Dennett thinks consciousness is an illusion” (a misreading that he, to be fair, could work harder to discourage), but that’s not the view. His argument against the philosopher’s qualia is pretty compelling, and doesn’t imply that people aren’t conscious. See “Quining Qualia” for a pretty accessible articulation of the argument.