I suppose with that distinction between mental illness and brain disease, I can agree. I do think brain disease can increase the risk of addiction, however. Also sometimes it is very difficult to make that distinction.

Going by dictionary.com disease is "A pathological condition of a part, organ, or system of an organism resulting from various causes, such as infection, genetic defect, or environmental stress, and characterized by an identifiable group of signs or symptoms." So I would say if your belief structure could be considered "pathological" it would qualify as an illness. Personally I would say that any set of beliefs that causes harm to an individual can be considered a disease.

I believe that people who choose to treat themselves as victims will choose to treat themselves as victims, whether or not they have a convenient label. Many of these people do use labels as excuses, but I think they would assume victims roles regardless. In my opinion they want to believe they are victims, and they will use any tools at their disposal to reinforce that belief. I don't think the label itself is actually causing harm. My view on the stigma surrounding mental illness is similar - I think the stigma was actually stronger before the labels, and now that mental illness is coming to be understood that stigma is diminishing.

With regard to CBT, I agree that it is effective, but I also think it's limited. Other approaches to treatment are also very effective, and in some cases necessary. Group therapy, medications, humanistic therapies, and even treatments like ECT have their place. Labels help determine which treatment to administer when. Even cognitive behavioral therapies aren't universal. For example, patients with borderline personality disorder don't respond all that well to REBT - but they do respond well to dialectical behavioral therapy, a different CBT which takes the specific diagnosis into account.