Just a quick word on the origin of this much used, much abused and much misunderstood word "fundamentalism".
In 1909 there appeared the first of a series of 12 paperback volumes under the title The Fundamentals (I have a full set). These were mailed free of charge to "every pastor, evangelist, missionary, theological student, Sunday School Superintendent, YMCA and YWCA secretary in the English-speaking world *" Over 3 millions copies were eventually circulated.
The booklets were a protest against what was felt to be a considerable drift in protestant theology in the late 19th century caused by the growing popularity of Darwinism and High Criticism - a scholarly methodology providing new tools for the interpretation of the Bible.
The authors of the papers in The Fundamentals were some of the finest evangelical preachers and theologians of their day; men of great learning and repute.
The Fundamentals were a call back to what the publishers believed to be the core issues, the basics, the FUNDAMENTALS of the historic Christian faith. They rebutted both Higher Criticism and Darwinism and re-affirmed their belief in the full verbal inspiration of the Bible as being the infallible revealed word of God, the nature of man as a sinner, the divinity of Jesus Christ, his atoning death, the necessity of faith in Christ for salvation, and so on.
The Fundamentals proved to be a rallying point for those who were of this persuasion. And just as the early followers of John Wesley were dubbed "Methodists" by others, so the adherents of The Fundamentals became dubbed "fundamentalists". As we know, this theological position came in for some abuse during the famous Scopes Money trial when evolution/creation became the nub of the issue.
But note: These 'fundamentalists' may have become somewhat naive or simplistic as time went on, but they never became political extremists. They did not take up guns and bombs in defense of their religion. That would have been antithetical to all they believed. They were mainstream evangelical protestants. Period. To illustrate, Billy Graham is a good example of a true fundamentalist.
So you can see there could be no such thing as a 'Catholic' fundamentalist. Even less so could you have a 'Muslim' fundamentalist, let alone a 'Hindu' or 'Buddhist' fundamentalist.
Yet somehow the word 'fundamentalist' got detached from it original meaning and misapplied to people who might be better described simply as extremists or religious fanatics. Whatever is the profile of these people it does NOT jibe with the fundamental teachings of conservative evangelical Protestantism - Fundamentalism.
If there is a common thread to be found in the abuse of this word it is an undue, blinkered and lop-sided adherence to whatever the religious adherent believes are his/her infallible scriptures. That can be very satisfying to simple minds which need simple answers.