AA has been called "a religion in denial." AA goes out of our way to explain, "We are spiritual, not religious."
First, for many secular AA's the word "spiritual" is never used in describing addiction or recovery. Personally, I don't find the word especially useful because it can mean anything to anyone so it's hard be concrete or descriptive with a word three or four people wouldn't agree on it's meaning.
Secondly, the secular AA meeting directory has grown from under 100 in 2000 to nearly 400 worldwide in 2017. That's not too exciting when contrasted against the ubiquitous nature of AA and it's 117,000 meetings worldwide.
Secular AA meetings for atheists and agnostics offer mutual aid without prayer and some of the more dogmatic and ritualistic practices of a typical AA gathering. In major North American cities you can go to a secular AA group any day of the week but for alcoholic atheists wanting the AA abstinence route in small town USA, they might have to rely on an online secular AA community.
This Fix story chronicles a case tyranny of the majority.
Most of Toronto's AA members are theistic although not many of them identify with the church of their upbringing. In 2011 the more religious Toronto AAs rallied to vote out the atheist, godless AA groups which, it turns out, didn't win them the support of either AA's General Service Office in New York or favor with the legal system when a complaint of discrimination was filed with the Ontario Human Rights Commission. In Canada, even if AA had a rule that members had to believe in some deity - a rule that AA does not have - accommodation has to be made for atheist members and groups who want the services of AA but who don't rely on supernatural intervention as part of their recovery from addiction.
The disruption, as it turns out, may have done more good than harm for the local godless prayerless AA meetings. While there were two groups that were delisted in 2011, there are 15 meetings in southern Ontario now, most of them being in the GTA. It seems there were some closet atheists/agnostics in AA that showed their support for these meetings once they were brought to their attention.
A number of circuit courts in the USA have deemed AA religious as far as the establishment clause of the First Amendment is concerned. Is atheist AA a dirty little secret that corrections and treatment centers are kept in the dark about? It seems that more attention to AA's atheist growth could help to lift the impression many have of AA as an old-fashioned approach to behavioral health/addiction.