Since cryptohunter has taken to using self-moderated threads to delete posts containing facts that conflict with his warped opinions, I'm reposting this here, as I feel it's an important and relevant fact that sane people might be interested in knowing and possibly discussing or debating.
If i tell a criminal that has stolen my money to give it back or else I will tell the police.
That is revealing a secret they have to do them harm. That is not blackmail that is reporting a crime you thick turd.
Putting it in large letters doesn't make it true. What you're describing is, indeed, blackmail. But don't take my word for it: just ask the police whether it's okay to not report a crime because you talked the criminal into returning what they stole. Letting criminals get away with it in this way allows them to commit further crimes, which is why offering these sorts of deals is illegal. You're obviously not likely to get arrested for doing this, since the criminal is the only witness to the blackmail, and they can't implicate you without confessing to their own crime, but blackmail is still illegal even if you won't get caught.