I hear you, Michael, it is so frustrating. There *are* people out there who do take trauma and dissociative disorders seriously, but unfortunately if the ones you interact with do not take it seriously it can be very hard to find a way to get yourself to the ones that can help you. I am not in the US but have found this to be true in the countries I have been in.
I am currently trying to get myself treatment with a T who knows how to treat dissociative disorders. In this city I have tried 5 therapists, and number 5 (current, but only had three sessions) is the most hopeful, but I am still nowhere near certain that her understanding of DID is compatible with mine.
Keep searching!