Sticks and Stones

Why do we take such offense to insults, it's just words, I know that sounds stupid. Sticks and stones and all that shit, but really.... Why do we care so much about what people think of us as long as they aren't harming us? 

I was sitting in the pep band of a college basketball game cheerfully jeering and cat calling at the other team, but some calls were too offensive... "Ra Ra Ree Kick em in the knee, Ra Ra Rass kick em in the other knee", just the implication of the word ass is too offensive... Tell me what you think is too far...