Fundamentalism, in case you don't have a dictionary
Fundamentalism refers to a belief in, and strict adherence to a set of basic principles (often religious in nature), sometimes as a reaction to perceived doctrinal compromises with modern social and political life.
1 often capitalized : a movement in 20th century Protestantism emphasizing the literally interpreted Bible as fundamental to Christian life and teaching b: the beliefs of this movement c: adherence to such beliefs
2: a movement or attitude stressing strict and literal adherence to a set of basic principles
Let's do some basic logic, kids. Fundamentalism requires principles. Atheism is not a set of principles. It is the lack of belief in a deity. That is all. Nothing at all follows from atheism. How many times do we have to do this lesson?
1. There is probably no god.
Nothing. Absolutely nothing. There is no principle that can be derived from atheism. Any set of principles that includes atheism cannot under any circumstances be derived solely from atheism, and must be founded on a second premise. Therefore, any fundamentalist who also happens to be an atheist must be a fundamentalist with regard to something besides atheism.
That is all.