There couldn't be anything more morally neutral than wishing the things that someone does to someone else happening back to them. If they're a good person, it will be like wishing good fortune upon them, and all is well. If they are an evil psychopath, only by acknowledging that what they're doing is malevolent and malicious could that person react in anger. Even then, it would be considered justice to get a taste of your own medicine, so you're still in the clear.