Fundamentalism is all about exclusion, not inclusion. Let's disregard for a moment the obvious exclusionary views of the Old Testament, and focus on the teachings of Jesus in the New. Actually, we'll have to go farther than that, we'll have to disregard various remarks from Jesus about saving the Jews only.
But let's assume the teachings of Paul, rather than Jesus, stand true. That Jesus Christ came to save mankind. Why do Fundamentalists make such an effort to exclude the rest of mankind? They are not to befriend unbelievers, and are never to even so much as think about entering a relationship with "heathens," as it was put so kindly by a Fundamental Preacher that I once met.
As a Fundamental, the most you can do is to "reach out" to unbelievers with your preaching, a manner which is hardly going to persuade the larger percentage of the population that your God is a loving God. So why the barrier of exclusion?
Speaking as a former follower of Baptist Fundamentalism, those barriers exist to protect an entrenched mind, to keep a belief system in place that is no longer compatible with the world we live in today.
If your God really has the power to sway minds, to make himself obvious to the "hearts of men," why be so scared of befriending unbelievers?
This is all just part of the philosophy of Fundamentalism that I could no longer agree with. The literal take of the Bible just doesn't work, with the numerous contradictions within the texts.
There's a time when everyone is forced to come face to face with reason; they can either abandon it by several methods, or they can embrace it and deal with the consequences that come to them. However, due to the nature of our imperfect world, not everyone will be forced to have the same bout with reason. One person may have a much tougher struggle with it than the next person.