Two possibilities I'd like you to consider. The first is that the effect of chemicals on these so-called diseases indicates the existence of a physical component.
The second is: what if there were a set of behaviors which were not a disease, but which responded to treatment as though it were a disease? I suggest that because I am inclined to agree that mental disease is not a disease in the classic sense. However, because it can in many cases be treated as though it were a disease to good effect, I'm not sure that being technically correct on that count serves any utility. Some of me still cringes when I hear "the disease of alcoholism" but I no longer hesitate to use the phrase because I've found it to be a useful bit of shorthand.
You seem to share most of my understanding of the nature of addiction and choice, even if you phrase it differently. I will also acknowledge that I have not read Alcoholics Anonymous and that the only literature associated with the group that I have read is "Living Sober," which was helpful to me on my quest for sobriety, though I found I had to "cherry-pick" my way through it and I feel that if did not take that approach it may have been very harmful to my development.
I have been taking care to avoid some of the jargon because I agree that we have a lot in common when it comes to this subject, yet we seem to have come to some very different conclusions.
A piece of perspective that may be helpful (and which is probably not obvious) is that the book Living Sober is very much intended for people who are very newly sober. Its aim is by and large to help people survive long enough to get into a deeper process of recovery. That's not to say that nothing in there applies to later recovery, but that's not its focus. I agree that by itself it may not send the right messages. If that's the primary source of you knowledge about how AA works, it's easy to understand how you could have arrived at some of the conclusions here.
I'd be lying to say it wouldn't be possible to get some of those ideas directly from AA meetings, too. One thing that is important is that there is no real hierarchy to AA. Stuff that people say in meetings about how AA works is often well-meaning and sometimes good advice, but sadly only infrequently is it representative of the program of recovery set forth in the book
Alcoholics Anonymous and expanded on in the book
Twelve Steps and Twelve Traditions. There is no screening of content to make sure it is in line with the literature, and that is a good thing, because AA is purely a group of peers. It works better without authority than it possibly could with.
(Alcoholics Anonymous is in fact much like Bitcoin. It is open-source and noncentralized. While there are central offices that maintain schedules, organize phone hotlines, keep bookstores, and whatnot, those central offices are responsible to the groups, never the other way around. They could be disposed of without much more than a decrease in convenience. And there are a ton of alternate fellowships with a few variables change but running the same software. And some people make physical coins to represent it. I could go on.)
You also made mention of a higher power, briefly. I should note that I do not believe in a higher power by most popular definitions, but I contemplate that just maybe, perhaps...
I've seen people air gripes about AA enough times to be utterly tired of the people that get hung up on the God thing. I probably would not have replied if part of this were about how AA is pushing Christianity on people. Once someone has formed that opinion, it's really hopeless trying to discuss anything because of the lack of common ground.
I can call myself a believer about as honestly as I can call myself an atheist. What I call God, many people don't. My use of the word has become very fluid as the fundamental concept I have of God is that It is (not exclusively but almost totally) outside of me and independent of what names I give It or stories I tell about It or ideas I have about It. Put more simply, my opinion does not alter the reality around me, it alters only my stories and opinions. I believe we're all—from atheists to the most fervent literal theists—telling stories about the same thing despite how different the stories are.
The "higher power" might be consciousness itself (as in The Self Aware Universe by Amit Goswami), or that possibly all existence consists of various representations of some core essence, in a self-similar manner (i.e. each atom contains the entire universe, as you zoom in it is repeated infinitely, as you zoom out it is repeated infinitely, but perhaps with no individual "scale layer" being exactly the same as the other, rather being equivalent mathematically but represented differently at each scale). In this model I see every element of the universe being representative of all the others and the whole shebang, so that theoretically with enough knowledge about any given atom one could understand the entire universe. Likewise, in this model it does not matter what you study as all knowledge is equivalent, the more you understand about any one thing (say Mahler's Ninth Symphony for example) the more you understand about the universe at large; all understanding is "portable" or "universal" and a complete understanding of anything, whatever it may be, equates to enlightenment.
That sounds like it's working for you. Our stories about that higher power aren't tremendously different.
And um. Anything I may have said about Alcoholics Anonymous should be taken with at least a grain of salt. I do not speak for Alcoholics Anonymous, nor do I claim to be a member of Alcoholics Anonymous. I do describe myself as a recovered alcoholic; I haven't taken a drink in 17 years. I have therefore had occasion to come into contact with a number of AA members, its literature, and I may have seen the inside of a meeting a few times.