I have accepted that some "disorders" are genuinely caused by the brain or body functioning in a way that is dysfunctional or wholly negative, but many "disorders" are not dysfunctional or negative at all, or just so in some cases and not others.
As my prime example, Autism Spectrum Disorder never struck me as a disorder. I have it and I consider it less of a disorder and more of a personality type. In fact, if anything it is an overly ordered mind. Neurotypicals always struck me as so messy and illogical. Calling ASD a disorder seems at best uncharitable and at worst factually incorrect.
I think the compulsion is to put "disorder" on the end of any diagnosis which is "outside the norm", which is as good as saying "If you're not like me, you're wrong" which is extremely unproductive unhelpful and unfair, and only serves to make people reject their diagnosis or worse, themselves.