No, they do not. Being vengeful is never the best answer as it's highly immature and counterproductive. You can get past the trauma that happened without needing revenge and no form of revenge will bring anyone dead back, it's a waste of time.
It would still be a terrible inhumane thing to make him suffer, as it would not have any purpose outside of people having a ''justice served'' fetish. I believe it's much better to not perpetrate the morals these murderers might have, and instead challenge their morals by rehabilitating or imprisoning them. By torturing someone who tortured others, you're showing the world that you're willing to act just as bad as them, even if you could have the power of being the bigger person. And also, nobodys ignoring what he did, some of us just prefer actual justice instead of the ''justice served'' fetish. Eye for an eye is not actual justice.
To add, you honestly cannot tell if a person will become vengeful after something personally happens to them. It's of course possible that they feel this way because nothing has actually happened to them, but some people are simply not vengeful and see no point in vengeance in the real world.
