A truish story with all names and many circumstances altered:
Alice and Bob were friends, but their friendship had seen some rough patches recently due to an ill-advised business experiment and some ensuing uncomfortable feelings. Today they were co-working, with the intent of mending whatever was broken through dedicated inattention. The two of them sat down in Alice’s kitchen. Bob took out paper, pens, and a loud bell. He picked up the bell and proceeded to pace back and forth across the room jangling it with the vigor of two arms and staring into space.
It turned out that Alice loved the sound of loudly jangling bells, which reminded her of the beautiful church she used to live next to. And she was working on her own general solution to coordination problems—a puzzle so fascinating that she could not possibly be distracted, even by the delightful bell song. So the noise caused Alice no suffering.
However, Alice reasoned that Bob had no way of knowing that she would not be harmed, and that he really should have expected that his bell-ringing would annoy her a lot in expectation. So she had little choice but to infer that Bob didn’t care about hurting her. And that did hurt.
Furthermore, she reasoned that Bob must be aware that she would be hurt by observing that he didn’t care about hurting her. So he should have anticipated not only some suffering in expectation from the bell, but also this second level of more certain suffering from observing Bob’s indifference. Knowing that he was happy to deal her even that much suffering was even worse. And furthermore he didn’t even care about this extra suffering!
On top of that, she reasoned, once there is enough common knowledge of enough certainty of enough suffering willingly inflicted, Bob can’t be doing this by accident. It becomes an intentional affront. A message of hatred, rather than an inadvertent sign of indifference.
She became extremely angry and marched out of the front door.
(Bob made a mental note that Alice really didn’t like bell sounds.)
Knowing that someone knowingly hurt you is hurtful. And knowing that someone knowingly hurt you by indirectly causing you to know that they knowingly hurt you is hurtful. And so on.
I suggest that social injury often has this character of being magnified iteratively by approaching common knowledge.
Perfectly legitimate offense doesn’t even need to stand on the ground at all. Suppose that I like being slapped in the face. Also, I know that you know this. But I also know that you don’t know that I know that you know that I like being slapped in the face. Then you slap me in the face. I’ve got to figure you are willingly harming me with your seeming desire to harm me, even if you don’t think I will actually mind the slap per se. Alice was reasonable to be upset, even though she liked the bell sound.
I expect something similar can happen at a group level. There is an action that hurts a small fraction of some group of people. Then doing it indicates that you are fine with a chance of hurting people from that group, which hurts the feelings of the whole group, and causes enmity with whatever groups you are saliently a member of. Then if people continue to do the action, the victim group takes it as an even larger sign of disrespect and at some point an intentional slight. Then even if the action ceases to hurt anybody on the object level, or is replaced altogether by things that are thematically similar but not object-level harmful, it has become a slight, and continues to hurt, because connotations are hard to erase. I don’t really know if this happens—I don’t keep up with current offense. More informed opinions welcome.
This theory predicts that actions would often be offensive in spite of probably not directly harming anyone on the object level. I think this does happen. I also guess that it leads to some confusion around whether other people are just pretending to be offended. (I also expect people sometimes are pretending to be offended, because often there are incentives to, and at least some people respond to incentives sometimes).
I also wonder if something like this explains why people jump on random insensitive statements that weakly suggest offensive views, even when there is no chance that the person holds the offensive view in question. If I really believed that someone thought I was good at drawing, but I also heard them accidentally momentarily imply to someone else that my drawings were rubbish, I would figure that they weren’t very interested in whether this might hurt me. Also that they might be trying to intentionally anger me. And people intentionally trying to anger me can be angering.
I posit that offense should almost always be out of proportion to the action that caused it. Hurtful actions automatically snowball into being more hurtful, and the offense of the victim is a response to the hurt accrued by the time the snowball lands.