The great deception in fundamentalist Christianity is that it sees itself as the real deal and anything else as coming up short. Fundamentalist Christians live in a different world. They believe in a God that acts in mysterious ways to the benefit of the believer. (Peter Sellick)
In seminary, the problem of "fundamentalism" was a very real issue, and energy was easily spent trying to "rebut" fundamentalist "arguments." Until you realize, fundamentalists don't have arguments. They have convictions; but not arguments.
To some Christians, all Christianity is a matter of faith, and all arguments stem from that faith. If you believe, nothing should shake your conviction. If you believe, nothing should be in question, either. There are fundamentalist and archly conservative (and archly liberal, too, let's be fair) arguments arising from Christian doctrine. But they are not apologia; they assume the truth of what is stated, and seek to bludgeon the audience into accepting the premises which are never questioned.
In short, you can't argue with "them," because you aren't speaking the same language. And you never will. Unless you agree with "them," of course, and then, why argue?
("Them," by the way, is in quotes because we should always remember not to demonize those we disagree with. But it's a convenience for the moment to speak of a faceless group. It's only a convenience, however. To take too firm a stand is to privilege ourselves over others, and that's a trap humility always warns us against. Though it's always hard for us to listen to humility).
How does God act in the world? That's a question of theology; and theodicy; and soteriology; and Christology; and even history. Fundamentalism reduces it to a simple known: God acts as interpreted in the revelation in Scripture. Obviously there are several questions there: which interpretation is privileged to be accepted? Which scriptures? And what is the basis of knowledge: revelation, or discovery? This is one of the the fundamental dichotomies in Western civilization: Hellenistic epistemology rests on discovery; "Hebraic" (basically, "eastern") epistemology rests on revelation. It's a crude distinction, but ultimately a useful one. Fundamentalist theology rests solely on revelation. But then there is the matter of interpretation.
Which gets us into the Bible itself, actually.