Probably the actual diagnosis determines how much focus should be placed on it. I've said this before. A bipolar diagnosis requires different treatment than a major depression diagnosis. In fact, if someone with bipolar disorder is treated with anti-depressants because they are mistakenly diagnosed as having major depression (which is a common problem), the anti-depressants often throw the patient into mania.

My diagnosis is vital so that doctors who treat me don't make those kinds of errors in treatment.

Some other diagnoses aren't reliant on or reactive to specific medications, etc., so that kind of issue doesn't really come into play.

Personally, I feel if a therapist has a client who clearly displays symptoms of a major psychiatric illness such as bipolar disorder, schizophrenia, major depression, etc. and doesn't talk to the client about what they are seeing nor discuss what options they might have as far as specialists, etc., then the therapist is being negligent. Probably isn't so vital with some other disorders that generally don't have a medical treatment available as an option.

Therapists need to have some common sense about this issue and remember their own advice: nothing is completely black and white.