Here's the deal: some people have the intelligence and manners of a slug. They are insecure and need to make fun if others. Anyone they consider to be different from what they perceive as the norm has the potential to make them feel somehow marginalized. So, they need to put you in your "place" by belittling you any way they can, and laughing at you is the prime candidate.
I pity their condition, but they are a real pain in any civilized society.
just my two cents.
