Sadly, this isn't the first complaint we've had about Catholic bashing at AA meetings. As you can read here, this gentleman had similar experiences.
MT's experience is particularly offensive because of the cowardice of the members who behave so insensitively toward her religion, then use that cheap "cop-out" trick "but we're only joking!" IMHO, if you're going to mock someone's beliefs, the least you can do is face up to it instead of hurling insults, then running away and hiding like little 10 year-olds by pretending you were only kidding.
There are many problems with 12-step programs such as AA, which you can read about here, but it's important to remember that these groups are run independently which means no five groups meeting in the same area will be the same. Some have phenomenal success rates (with no bashing of anyone's creed, race, gender, etc.) which means you have a good chance of finding a better group that will leave you feeling supported and encouraged - not alone and ridiculed.
Another idea might be to found a group in your parish which will probably attract a mostly Catholic membership and thus cut down on the Catholic-bashing.
May everyone who reads this blog say a quick prayer for MT and everyone like her who is struggling with addiction, that they might find healing and hope in Our Lord, Jesus Christ - and all the support they need from us!