Rather, I’d intended a much more utilitarian point: it’s good because it helps train people out of their bad behavior, possibly preventing future “victims”. It’s not necessarily about helping the actor, and it doesn’t have to be.

It’s easy to lose track of these points because we so often think of good people as being “nice” – but niceness can often imply this exact problem, of servility and conflict aversion, in a way that ultimately isn’t good for the nice person or those around them.

Presumably, to suffer injustice is to allow someone else (here, the “actor”) to commit injustice, by intent or ignorance on their part. If the victim (“subject”) stands up to the actor, this will -one hopes- discourage the actor from behaving this way in the future, train them out of their callousness or obliviousness.

Will the actor’s life actually be better if they become more virtuous? Quite possibly not; that’s a big problem with virtue ethics. But it will probably make life better not only for the subject (which one may or may not consider justice), but also for other future potential subjects.

I’ve toyed with the idea that there shouldn’t be any such thing as moral blame; Śāntideva says words to that effect. Ultimately I disagree with him, at least to the extent that we are trying to live in the everyday world and not rise above it as monks. But I do suspect that blame often plays more of a role in contemporary ethics than it should.