Don

There are a few things that one party in an argument can do to show they are fearful of losing and one is to resort to ad hominem attacks.

I think part of it is a lack of humility.  It goes something like this:  I am a believer and when I read the Bible it seems to say X to me, therefore it should say X to everyone.  If you think about this, this is actually an arrogant claim to infallible interpretation, but it does not seem that way to the believer.  It does not seem like arrogance at all, so it must not be arrogance.  Notice the lack of humbleness forms a chain.

Contrast that with sharing, this is what it means to me and why and I listen to what it means to you and why.  I cannot force you to accept my understanding and vice versa, but we can share our reasons.  Perhaps we think that we could not in faith do what another does, then the answer is to not do it.