I didn’t know that about bipolar being an excluded pre-existing condition. But I agree, you’re not bipolar anyway. Not from what you’ve described here.**
I do know there’s kind of a dance between the psychiatric community and insurers – most therapists know which diagnoses carry which implications with major insurers. They don’t really have time to pore over the whole DSM-IV for each and every patient, looking for the specific cranny that describes them best. “Depressed”. That’s what most people start out with. My therapists have asked me if it’s OK to use that one – you could tell yours on the phone, before you even have your first appointment, that you’re concerned about insurance and want to start with a simple “official” diagnosis. See what they say.
Therapists don’t look for more specific descriptions and categories unless it’s warranted by the patient’s need for treatment. Their only real goal is to work with you and your insurance plan to see that you get as much treatment as you want and need and can afford. That’s all.
Plenty of communities have mental health clinics with sliding scale fees – they don’t even HAVE to go through an insurer.
See, this is what you don’t get, because of the nature of your specific condition. Therapy is about a relationship. A relationship between a patient and a doctor. It’s not about categorizing.
It’s not about controlling, either.
Seeking involuntary commitment – do you realize how much work that is, for a therapist? They don’t have time to mess around with that unless there’s a HUGE crisis, and I’m saying HUGE.
If you come in with an uzi, yes, they’ll call 911. If you come in and say “Well, I’m planning to kill myself on Saturday by jumping off of the State Street L platform” then yes, therapists have an ethical and professional obligation to act. Just like any other member of society.
If you say, “I’m depressed, and there have been times when I’ve felt suicidal” they’ll ask “Do you have a plan?”. If the (honest) answer is no, then there’s nothing to worry about.
If everyone who was seeing a shrink were to be committed, locked away, there’d be nobody left to run the world! 
Seriously, the streets would be half-empty.
From your posts here, I think, and it’s totally my opinion, but I think you’re ready to start letting go of a little bit of control, and to start revealing yourself a little bit. Therapy is a safe place for doing so.
It’s a place for telling your story, not a place where someone else “fixes” you. It’s not about learning to please them.
Now, I do know for a fact that not all therapists are the same. But I’ve also experienced that the “bad” ones just don’t really care and don’t have much that’s interesting or valuable to say. I saw one who, I’m telling you the truth, used to yawn while I was talking! Sucker sat there yawning!! We didn’t get very close, obviously. He was of limited use to me. But he DID recommend some books that I found helpful, and just going in and telling my story was somewhat helpful anyway. Kept me going. I learned a little bit.
A few years later I found an outstanding therapist. Vastly different experience. Within 6 sessions, my world was blown wide open. BUT – I was ready for it at that point! Earlier, I wasn’t. I achieved huge healing while working with him (and notice I say that I achieved it – HE didn’t do the work, I did!).
There’s a saying “When the student is ready, the teacher will come.”
I think it’s great that you’re exploring these issues here, online.
My favorite book on the subject is If You Meet the Buddha on the Road, Kill Him by Sheldon Kopp. The outstanding therapist recommended it (I was like, aren’t you gonna tell me to go read something?).
** IANAD, obviously, that’s merely my opinion.