to determine how "so" inadequate inadequate is.
I do appreciate that the 'why' of your question may be of greater interest to you, but you may find that 'so' pathetic is actually not 'SO' terribly pathetic.
Self-assessment of this nature isn't particularly technical, most of what the assessment considers are fairly resistant to biased perception that can exist while feeling troubled. As always there is a risk of learning things which, if one is inclined to do so, could facilitate mimicry of symptoms and that would exacerbate rather than help.
Institutions/agencies use the assessment more than psychologists. And it seems that it's therapeutic use has diminished rather than strengthened. That could be for various reasons two of them being 1) the scale is rather more arbitrary and less quantitative than it appears, and 2) clients present with mixed features which therapists prefer to consider as a holistic blend to be interpreted thru their expertise and experience rather than in terms of a checkmark identifying the most severe feature or features.
Nonetheless, the mGAF is an external standard of comparison which may help you find more objective meaning of the "so", in your question.
Various authors and agencies have modified the Global Assessment of Functioning to facilitate making distinctions within the intervals of the scale. The link takes you to such a scale which is already reversed compared to the outline in the DSM and which has suggestions for how to find ranges within the intervals. Generally speaking assessment proceeds until criteria match the function of the person being assessed.
http://www.bjcbehavioralhealth.org/uploadedFiles/BJC_HealthCare/Clinical_Specialties/BJC_Behavioral_Health/ModifiedGlobalAssesmentofFunctioningmGAFScale.pdf