I don't think atheism is a form of religion.
Not technically, but religious feeling and devotion can be found applied to anything. Similarly, some people classify themselves as religious but don't feel any particular attachment to it in a particular form, or practice it.
I disagree with ISFP's; perhaps there are a lot of religious ones I haven't met, but they seem to be too apathetic for it.
I agree with the person who says that religion and spirituality would have different pulls for different types and with the person who said it is important to distinguish between the two, but there may be some who would be more likely to be attracted to it than others.
I would say for:
religion: SJ if they grew up in a religious environment because they tend to value convention and establishment, Fe dominant because it allows external expression of feeling and a sense of community.
spirituality: Ni dominant because of the mysticism, Fi dominant because of the personal sense of meaning.
Ti-Fe enjoys theory and may enjoy theory which engages Fe, so might happen to be attracted to theology.
Edit: Se dominants seem to be attracted to it too, but I don't know why.