Earlier quoted context omitted.
It sounds like you've had a bad experience with a former employee, but this is not blackmail. That's just standing up for himself. The OP was working there contingent on his boss's promise of a raise, and both parties knew this, including the boss. In fact, the OP was remarkably generous towards his boss by doing something very foolish: knowingly taking an unlivable wage out of trust that the boss would live up to hi…
It sounds like you have done this in the past, and it is blackmail. And I understand that you don't want to see yourself as a blackmailer. "I'm more worth than that" and leaving is standing up. "Give me more money or I leave" is blackmail. "Regarding your Wikipedia quote, leaving a job in which you are abused and underpaid is not at all unjustified." Leaving is not the blackmail part, threatening to leave is the blac…
It is absolutely the correct call. He was being taken advantage of. He used his only point of leverage to get a fairer deal.