I agree that it has to do with empathy, but I wouldn't say it's projection. I think some people want others to suffer as a way to make others feel what they feel. So essentially it's a way of forcing others to empathize with you.
"Now do you see? Now you feel my pain. Now you understand."
At least, that's how I am when I'm in that mode.
This can even happen subconsciously. I would venture to say that any harm a person causes, they had to learn by experience or observation. I don't think the most harmful people were hurt the most, but they did have to learn the behavior. I've come to think that if you want to know how other people feel, just notice how they make you feel. This is especially true when the behavior doesn't make any sense in the current situation.
I was once close to someone who was very angry at their father, and didn't realize that they were hurting me/others in the exact way their father had hurt them. He would say beautiful, wonderful things, but his actions were completely self-absorbed and entitled. I had a chance to have conversions with the person's father and he was exactly the same way. That was a completely unconscious connection for that person. It is a good way to increase self awareness - to learn how we hurt others and try to relate that to how we have been hurt.
I have one I do myself. I've been hurt by neglect and disregard, and I have caught myself becoming distant with people I care about. It's hard to correct it every time I do it, but there is definitely an unconscious connection with reenacting how I've been hurt. For myself, I think it feels like regaining balance or control over the original feelings of neglect. Now it's just something we all do. It feels less personal. I suppose that could also motivate bullying, aggressive behaviors?
Edit: I should add that this thread is awesome. It is really cool to see so many people with very high emotional intelligence. All the responses are spot on, kind, and deep.
