man no longer becomes as soceity cages him.....Nietzsche

i am extremely interested with the topic concerning morality......the problem with it generally is that morals are not truly set in stone (what once was normal becomes immoral, what once was wrong becomes justified, etc).....anyway, the problem swings both ways.....yes society is wrong for caging man, but if it does not then chaos is possible....though not as likely as believed.....both society and man generally consider certain things to be immoral, such as murder, rape, stealing, neglect, human testing, etc.....but how far should society go to label morality? i mean soceity tends to view murder wrong unless you kill in self defense, or in some cases out of revenge.....but would you consider it wrong if i killed a convicted child molester over fifteen years ago, even if my vengence is on behalf of his victims and solely for me?