I'm chiming in her rather late, but here goes.
This is a great topic and congrats Lafemme on six months! Wow!
It's undeniable that AA had it's origins in a Christian group, the Oxford group But, it is interesting to note that the Oxford group was formed as a protest and a reaction to organized Christian churches. One of the tenants of the Oxford group was picked up by Bill W: and that was the emphasis on an individual path to spiritual awakening, rather than being guided on that path by organized religion. The Oxford group was very much a critic of organized religion.
From Wikipedia:
"Wilson later acknowledged, "The early AA got its ideas of self-examination, acknowledgment of character defects, restitution for harm done and working with others straight from the Oxford Group and directly from Sam Shoemaker, their former leader in America, and from nowhere else."
I am always intrigued by this because my experience with organized religion in the Catholic Church was that I didn't have to make any restitution for harm done, I just had to go to confession. There is something revolutionary about the ideas of examining character defects, making restitution and being of service to others. It is a very different idea than I got in the RCC.
Because the Oxford group was formed in negative reaction to organized Christianity, and because it's ideas were the groundwork for many of the 12 steps, it really can't be claimed that AA has it's basis in Christianity. Part of the reason for that is that there are so many alcoholics who aren't Christian, and who find a place in AA:
I went into AA as a thoroughly disenchanted Roman Catholic with massive criticisms of my church. In AA I found that only one religious concept is endorsed: and that is finding a path to a higher power. That is endorsed in most of the worlds largest religions so I don't think that can be claimed as a Christian idea exclusively.