I think what defines a cult is that it deprives members their individual rights (or free will).

In AA and NA 12-step groups, members freely choose to attend and/or participate in open or closed meetings. If you don't like your sponsor, you get a new one. If you don't like the god others choose to surrender to, then you pick another one. You don't have to contribute any money if you don't want to, not even for the free coffee. If you choose, you stay anonymous. I don't think AA or NA 12-step groups are cults.