Does belief in a higher power constitute being morally failed? Is it even specifically Judeo-Christian?
Being "powerless over your addiction" has more to do with setting aside rationalizations and not mistaking temporary breaks for having control.
AA undeniably has a Christian flavor -- it was developed and elaborated by Christian people -- but that doesn't mean it's about Christianity.
The emphasis on public self-flagellation and self-humiliation via drunkalogs and self labeling as “alcoholics” aka sinners, the insistence on the nonsensical idea of “personal powerlessness,” the dogmatic suggesting of a book (the AA big book) written by Christian religious freaks as if it’s the Bible...
AA quite literally IS Christianity. It’s just that they use the generic label “God” rather than the more specific label of “Jesus Christ.”
It’s not like they allow polytheism, lol. They are specifically a monotheistic group religion, based on the idea of a singular MALE “higher power.” AA is Christianity. Saying otherwise reveals you either don’t know much about AA, or you don’t know much about Christianity. They are functionally the same.
The entire insistence on the belief in a higher power, along with insistence that one is "powerless over your addiction" is intrinsically talking about a moral failing, and more specifically adherence to a christian-worldview where all from birth are morally failed.
They are offering a solution, in the form of rewiring your entire worldview (and deeply held beliefs) to the idea that you are powerless, there's an all powerful deity, and all good things are because of said deity. Step 4 is literally "Made a searching and fearless moral inventory of ourselves." [1] It may be effective for some, and some may have issues or resistance to such a thing.
Having a conversation about the methodologies is impossible without potentially discouraging someone from seeking help - but we should not hide the negatives, or else there'll be no way to actually get to better solutions. My feeling is that religion and giving up to a higher power can work for some people, but for others it can be a betrayal of their deeply held principles and values - my fear is that places like AA in an effort to evangelize their own principles and values take people who are rock bottom and offer up theirs as a solution rather than something that might work well for the person.
1: https://12step.org/the-12-steps/