Sometimes it’s really hard to tell the difference between justice and injustice. It’s the ethics of human that nourished “justice”. Ethics usually exist to protect the benefit of the majority and the equality of life. Take the “eating orphan” case for example. In terms of the consequence, at least 3 adults survived though one orphan died, which is much better than all of them starved to death. If they didn’t kill the orphan, a lot of suffering and load would be added to their families, which goes against the benefit of the majority. What’s more, struggling for survival is the human nature, so there’s no point of blaming them in such a special situation.
But in terms of their motivation, they murdered. The essential factor is that they decided their lives are more important than his-that is, my desires, my needs should take precedent, which offends the equality of life and also I think is often the basis of many crimes.
So, what is justice and what is injustice, I think it varies from person to person. That’s all.