It doesn't matter if they don't know what it's called. It's what they're taught in the commentary in all contemporary Catholic bibles and in almost all Catholic bible study groups. Just try to find one where it isn't. It's also pushed in articles in mainstream Catholic magazines, newspapers, publications, "apostolates," and web sites.
All this was invented by liberal Protestants. Yet Catholics have adopted it to discredit Biblical literalism and total infallibilty, which modern Catholics apparently can't tell from sola scriptura. I was in the Catholic Church for six years, and there were far more articles in Catholic publications attacking the facticity of the scriptures than there were attacking abortion!
Catholics attack "Fundamentalism" for "rejecting tradition" and teaching sola scriptura. But "Fundamentalism" doesn't teach these things. Protestantism does. "Fundamentalist" Protestantism is merely Protestantism that still teaches classic Protestant doctrines while the liberals changed everything and rejected everything supernatural. Liberal Protestantism also rejects Catholic tradition and teaches sola scriptura, but Catholics never criticize them for it. Instead they constantly engage in ecumenical activities with liberal Protestants (where they probably both spend all their time attacking Fundamentalist Protestantism). Now, if Catholicism is really against Protestantism, to always attack Protestant Fundamentalism and always engage with Protestant liberalism is counterproductive. But Catholics identify Protestantism as "fundamentalism" and then attack fundamentalism while clearly respecting liberal Protestantism as though it weren't Protestantism at all.
You'd think traditionalist Catholics could appreciate "fundamentalists," but Catholics can't call themselves this. To them "fundamentalist" is a dirty word, an obscenity, so even conservative Catholics attack Fundamentalist Protestants rather than liberal ones.
All words have a connotation as well as a denotation. Whatever the denotation of "fundamentalism" is, its connotation is that of persevering in the original supernaturalistic beliefs when everyone else has sold out. Yet it and not "Protestantism" per se is treated as the Ultimate Enemy. To me an attack on "fundamentalism" is an attack on remaining true, refusing to change, etc. That is the message Catholicism sends by exclusively trashing "fundamentalism." They make themselves sound like a bunch of new age loonies. Too bad they can't seem to figure that out.
I don’t know which traditionalist Catholics you’ve met, but a lot of our ire has been directed to the liberals and the Modernist heretics in both the Catholic Church AND the Protestant denominations.
I honestly can’t recall the last time someone at my parish launched an open diatribe on ‘fundamentalism’, relative to these greater heresies.