Fuck it, I'll write more because I am offended by people holding the position that all offense is a result of people being close-minded. The reason I am offended is because it irritates me that people use it as a excuse to be assholes and then tell others that they are in the wrong for getting pissed about it. I suppose real cruelty just irritates the hell out of me, especially when people deny being cruel. At least own up to being an asshole. I know I do, I post here about how I like guro and shit because I find it funny when media shows the world as being as cruel as it really is. And I'm unscrupulous in my interactions in real life, because being useless, I can't afford to risk anything.
You also just admitted that people being assholes isn't out of a desire to prompt the victim to look inward and re-evaluate the self, but because the perpetrator wants a reaction so he can assert his superiority. Also, my example was physical violence to remove the ambiguity associated with verbal abuse. People like to deny the pain of words, but the pain of the body is undeniable.
The blurred line between criticism and insult is probably the cause of the teenage tendency to assume anger is always a response to a painful truth being unveiled. This may sometimes be the case, but it is far from always. Let's take the classic example of trolls trolling the family of a suicide. Nothing is being learned; the family is already well-aware of the death, and of the reasons that could possibly surround it. However, they will be offended at people taking joy in their suffering, because being resentful of people being assholes is a normal response. When people are assholes they take advantage of others, which out of self-interest, people naturally find distasteful. The rage is not out of a fear of learning something new, but a hatred for those who would willingly make life more miserable for the rest of us. And when those trolls tell people that they should be thankful, that is even more enraging. How does the saying go? Something like don't shit on my plate and tell me it's gold...something like that.
In addition to the irritation of an insult, it irritates people further when insults hide behind the label of criticism. The difference between the two is intent. You just conceded that the intent of most offenders is to disrupt someone's mood, hardly a noble goal. And even if the insult could be considered valid, for instance, calling someone stupid who is legitimately stupid, the offense is not because the victim is confronted with a different worldview, but because someone just made a disparaging comment towards them. Even if meant as criticism, without tact, it does nothing to help.
Another thing people are offended by is cruel policies and other injustices. Arguably, this falls under the category of having their convictions challenged. People understandably are unlikely to be willing to understand a worldview that says that they have no rights. That does not make them petty.