If you have ever tried to tell friends and family about the dangers of Islam (and I certainly HOPE you have!) you've probably run into what seems to be a brick wall, at least occasionally. People seem to deliberately refuse to understand what you mean. Why?
In an article at Political Islam, Bill Warner has a great list of what's getting in the way of people really listening to you. He says, "Once you understand the doctrine of political Islam, there is a question that naturally arises. Why doesn't everyone know about this? ...It is not only that we don't know, we have also developed a systemic social theory of why we will not learn."
Those of us who want to reach the people who do not yet know what we know (and I should think that includes all of us) better clearly understand what this brick wall is made of, so we can fashion ways over or around it.
I think Warner's list is good. Probably a few more things could be added to it.
His list is (he explains each in more detail in the article):
2. What will we have to do?
3. I know this Muslim and he is nice.
4. Afraid of being called a bigot.
5. Islam cannot be worse than Christianity, so why learn?
6. It's too hard; non-Muslims cannot learn Islam.
I would add that you sometimes see a look in someone's eyes that says, "I think you're one of those nutballs who gets obsessed with some obscure paranoid threat, and I don't know if I should encourage this by listening."