Violence should only be done in defense of community and/or self. Reformative justice is good, and should be done wherever possible. We should stop the harm, then repair the harm. But that's only my opinion.

The real issue is that "revenge" is a bit vague. Oxford defines it as "something that you do in order to make somebody suffer because they have made you suffer". Restorative justice might well fit under that definition, because fixing wrongs and rehabilitation isn't easy. A painless execution might involve no suffering. I think we should at the very least avoid the use of the word, because of this. We want to stop harm and we want to fix harm, and we should talk about it like that.