They don't act stupid, they are stupid.

I have never noticed such behavior. Maybe because I don't get angry. I rather feel sorry for their fear of logic. A gentle heart is required in dealing with such people, never anger.

I don't think that it is intentional as most Christians I believe have never really questioned their own beliefs and are simply shocked that you do not share the beliefs they have, and therefore struggle to make a valid argument to what they see is an irrational argument

A lot of religious people sound stupid because they're playing by a completely different rule book when they argue. Arguments don't need to be rational or logical because the arguments defend God, and that's all that matters. They walk into arguments with an understanding that you're wrong, God is real, one day you'll "grow up" and realize this truth, and that whatever you're saying is just unfortunate misgivings that have led you astray. Whether or not they sound stupid isn't a concern because they already know that they're right anyway.

I think some people need religion to make things make sense to them. That is what they were taught and I actually believe that if most of them had to actually consider outside of what they were taught they would be lost.

I think it is pretty common for most ppl to not be able to see any other point of view once they have claimed one either from brainwashing or learning. How many adults consider the small intricacies of the learning process kids go through? What as an adult is common knowledge or common sense was all learned. Sometimes it is hard to change or to look back. Most ppl seem to like consistency. Some ppl fight change so hard it makes their teeth grind.