It's mostly automatic, I mean how could it not be after all we were raised to stand up for what we believe in. Taking offense to someone, something, a word or phrase that upsets us is normal, isn't it?
Every week I hear a new story about anti-bullying efforts in the U.S. and quite frankly it's all backwards. If someone teases or belittles you, it has nothing to do with you, and everything to do with them. They are afraid, afraid of what you represent, afraid of what it says about them if you are accepted by society.
It's important to realize that when someone says a negative comment about you, it's your choice to believe what's being said. A negative comment on it's own does no damage unless the ears it falls upon believe it.
Let's say I were to call you an "idiot". Now most people, if given the chance, would focus on myself and how what I said was mean and hurtful. But what's the problem? Are you an idiot? If not then what's to be offended about. If I called you a "three armed banana" you would most likely just be confused, certainly not offended. The difference in the second accusation is that it's obviously false.
The fact that you get offended at being called an "idiot" means some part of you believes that might be true, or that you will allow any random person to control how you feel by calling into question your sense of self worth.
Preventing bullying is a band-aid. Instead, teach kids not to determine their self worth through the approval or disapproval of others. I'll dare say that bullying and the feeling of being bullied are both a result of this social parenting staple.
Bullying, and being bullied, are two sides of one coin. We create that coin by teaching approval and disapproval from birth. Bullying, or disapproving, of someone or something promotes a sense of self-approval, or gains the approval of others who stand by your side in that viewpoint because it implies that we are right or "good" and should be accepted for our views. Feeling bullied, or disapproved of, by someone or some group of people does the same thing, only in reverse. If I believe and can get others to believe that the bully or seemingly hurtful concept are bad or "evil", that implies that I am inherently good by separating myself from that negative viewpoint, that I should be accepted or approved of in spite of them, and they should be viewed as wrong or "evil".
Both sides are attempting to achieve the same result, acceptance, either by inclusion of them-self, or the exclusion of the other.