Intelligent Response?

Recently, I re-read the entire Harry Potter book series. In Book 5, the reader is introduced to a new character, Luna Lovegood, who is portrayed as an eccentric, but loyal friend to Harry and his entourage. There was one running theme related to this character that irritated me and got me to thinking of how this same theme works in real life.

Every time Luna said something that was seemingly off the wall or merely not understood by those around her, and when she bluntly expressed truths that most people would cover up with insincerity, the common reaction of those around her was to giggle.

When something like this happens in real life, that annoys the hell out of me. It seems to me that someone laughing at something or someone they don't understand or something that makes them uncomfortable betrays that the person does not have an intelligent response. It would seem that if one finds something odd or they don't understand something or someone, the intelligent response would be to ask questions and learn something. To laugh at the person is simply to project one's own lack of understanding onto the other person. And not only children react in this manner; adults do it all the time as well.

And, usually, people don't wait until later to ridicule what the person has said - they laugh right in their face, as if the person has automatically forfeited any considerations of common courtesy by failing to act "normal". I don't get this. Even if the person IS totally off the wall, it doesn't necessarily follow that common courtesy no longer applies to them

Thoughts?