Can you provide a specific example of either a person or a website for what is meant by a "fundamentalist Catholic"? Also, can you clarify how this term is defined? Is the definition of a "fundamentalist Catholic" a Catholic who has offended someone?
You ask an excellent question. I think the idea of "fundamentalist" that you are thinking of relates to American Protestantism, and we should likely indicate it by using the upper case, so "Fundamentalism". The fundamentalism (lower case) that the Pope is talking about is not the Protestant (upper case) variety, but a general term that can be applied to people of any faith. I have done some searches and can't find one place where Pope Francis defines it, but in his usage in talks and interviews it appears that the meaning is assumed to be understood.
From what I can find so far, and from my readings of various Pope Francis documents, the term "fundamentalism" refers to people who are militant in their orthodoxy, who see themselves as the great defenders of the faith and who say we must strictly adhere to certain rules, ideas or beliefs, as THEY understand and interpret them. In addition, some fundamentalists believe their way is the only way to God, to salvation, and that anyone else, even members of their own faith, who do not follow their strict "way" are infidels, heretics, etc.
Pope Francis has brought up this fundamentalism, which he says exists in all religions, in several talks and documents, including his Apostolic Exhortation,
Evangelii Gaudium. In his talk before the Pontifical Council for Interreligious Dialogue in November, 2013, the Pope uses words very similar to his response to the question during the flight back from Africa. In that talk he mentions the "tragedy of narrow mindedness". In other documents and talks he mentions the challenges of fundamentalism, which "demeans the dignity of every man and woman and exploits religion". A search on the Vatican website shows that both Popes JPII and Benedict XVI had brought up the problem of religious fundamentalism (lower case) in some of their speeches and writings.
In my view, the fundamentalism that exists in the Catholic church is with those who expect every Catholic to think like they do, because they see their view as the only correct one. Anyone deviating from their way of thinking, talking, and acting is considered at least a "cafeteria Catholic", and maybe a heretic or apostate. And some of those "fundamentalists" viciously attack those not completely on their side. One can see that easily by what some of these Catholic fundamentalists have posted on their websites and forums, and by what the Pope has said several times.
The Catholic fundamentalist in general seems to view anything proclaimed outside the period from the Council of Trent to the time of Pope Pius IX to be suspect, ignoring the 15 centuries before Trent and most of what has occurred in the past 150 years. More "liberal" fundamentalists are okay with most of what the Popes have done up to Pius XII, but not much since (think SSPX schism). Popes JPII and Benedict XVI were sometimes okay with Catholic fundamentalists, but even some of their words and behaviors were suspect (such as praying with Muslims and Hindus). This view means, of course, ignoring most of what has been done by the Magisterium from Vatican II on. The fundamentalists do not like change, while forgetting all the changes that occurred in the fifteen hundred years prior to Trent, the changes Trent itself made, and how the Church as evolved since, especially in the past 50 or so years.
The big problem, which I believe the Pope is referring to, is the attitude of some of those in the hierarchy, including the Curia. Hence the tough talks he gave to the Curia in December of 2014 and 2015, and how he has set up commissions and synods to perform some tasks previously done by the Curia. As we have seen from several prime examples, many in the hierarchy are self-absorbed, concerned much more with position, power and pomp than they are with advancing the Gospel and the needs of all the Church. They are the opposite of what Jesus commanded his Apostles to be, that is servants to all. They hurt the Church in several ways, one of which is to create divisiveness within the faith, both among the hierarchy and the faithful. For some strange reason, they see this as doing the will of God.
Just as we have in our political system (it may surprise many younger people to know that there were once liberal Republicans and conservative Democrats), our Catholic faith has become more polarized by this. It may not be as apparent to most of us on the parish level, but it clearly exists.
