Do the laws of retribution still apply.

I was thinking about this today after I accidentally did something that someone claimed was hurtful to them. Once they brought it to my attention, I said I was fine with them doing something of equal hurtfulness back. Which is is reasonable since they claimed I hurt them. As with every other time I have said this, they declined looking horrified that i would even suggest such a thing. It kind of seems like alot of people are taking the nice guy approach, whether it's genuine them having no desire to get even, or trying to send me on a guilt trip that in no way is going to happen.
The first (problem) I see with this, is that if someone did hurt me in a major way I would have no problem with doing something satisfactory back. The second point, about them genuinely not caring I believe. But the part of me that occasionally sees the worst in people can't help but think that they are trying to make me feel bad about them just taking it.

In the end it's not a big deal at all, but at the time it just seemed strange. Having not done anything terribly interesting aside from going to school, I thought this might make a good open discussion if there's any to be had.