Fundamentalism arose in the early 1900’s in response to liberal modernist theologians who started questioning some fundamental Christian beliefs such as the inerrancy of the bible, miracles, etc. Their effort is a rear-guard action since within Protestantism there is no machinery to uphold the fundamentals, unlike in the Catholic Church. The very purpose of Protestantism is to question, protest, and reform. Therefore, by its nature, Protestantism is reductive, eventually questioning everything, even scripture. So we would expect that the fruits of the Reformation would be eventual reduction of Christianity to nothing. “By their fruits you shall know them.”
So fundamentalism came to be. Too bad that these people who wanted to preserve Christianity did not realize that the Catholic Church is the God-given custodian of the basic fundamentals of Christianity.