[infotainment]

Sure, that works for some cases, but what if the crime already happened? For example, what if your house was broken into and your stuff was taken?

In that case, would your only recourse be to hire a private investigator to identify the culprit, and then personally show up at their house to exact your revenge? That doesn’t seem sustainable.

[TotalCrackpot]

You can look for info and help in your local community for example. You don't need to extract revenge necessarily, if you find that person you can organize with some people and visit them to take your stuff back.

[infotainment]

What if the person who stole it doesn't want to give it back? What if that person has their own group of friends-with-weapons?

We now a standoff between your private army and someone else's. Seems like an extraordinary inefficient way to achieve justice. (And, one that will likely end up being quite deadly for all parties involved.)