I've been there too many times to count - a discussion with a religious person which seems absolutely impervious to Facts. Actually, it doesn't even have to be a religious person, it can be people holding very strong opinions on everything from political to economical to social to aesthetic to any type of issue. I know that I am correct, I can present plenty of evidence for my position and why the opponent's argument doesn't hold, but they are impervious to it. Why is it that my Facts don't work?
It is because the other person are convinced they have Truth. Having absolute certainty negates the need for Facts. There is no way to challenge Truth with Facts as they operate on different levels: Truth is underpinned by belief and Facts by evidence. A believer will usually have found a person or persons they trust to tell them the Truth, which is why most believers are followers. Since they do not trust me, especially since they've been warned against me by those they trust, there is no way they will let what they consider to be my Truth challenge their Truth.
Of course, there is no such thing as the Truth. But that's a Fact, and good luck trying to convince a zealot of that.