To the extent that organized religion reflects the stratified nature of our society, it does so because people tend to go to church with others of the same general economic and social status. While there is some degree of diversity within any sect, religious groups in the United States do tend to be somewhat different from one another in the socioeconomic status of their members.
In our society, there are sects that tend to be richer and those that tend to be poorer. The richer sects are the more “mainline” or formal churches. These are churches like the Methodist church and the Episcopalian church. These churches are known for being more formal and perhaps more staid in their worship. By contrast, the smaller and more enthusiastic sects tend to be populated by a larger number of poor people. Churches like the Baptist church, the Church of God, and the Jehovah’s Witnesses have members who tend to be much less affluent than those of the more formal sects.
The question, then, is whether this stratification is a cause or an effect of our stratified society. I would argue that the latter is true. Our society tends to be stratified to a high degree and people of certain socioeconomic statuses tend to socialize with their peers from the same class. This tendency extends to religion. We can say that the economic segregation in our organized religion comes about because of the general class segregation that exists in most areas of our society.