Here is a good historical look at the underpinnings of what has become the modern fundamentalist movement. The IFB’s (Independent Fundamental Baptist) eschew denominational ties vigorously in their speech. But make no mistake, there is a hierarchical structure of rulers, bylaws and regulations that regulate membership to this exclusive club.
The following is a transcript of a seminar given by Phil Johnson (director of Grace to You) at the 2005 Shepherd’s Conference.

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This is where unbiblical exclusivism arises. I left a church that admittedly and proudly practices a ’separatist’ philosophy when it comes to extra-Biblical matters. There is no getting around the fact that the church does not include everyone. Peter refers to us as a “chosen race, a royal priesthood, a holy nation” ( I Peter 2:9). But exclusion of people from the church should never be taken lightly. It is a very serious matter. Schools and clubs and societies can set up any human regulations they wish in order to keep certain people out and preserve by rule a particular atmosphere. But the church is not man’s institution. It belongs to Christ. He is the head of the body, and he alone should set the entrance requirements.