No, it's a negotiation at that point. I'm not a lawyer, but I'm fairly certain that the difference lies in whether or not you make a demand. If you simply say "I'm going public with this info on X date" and leave it at that, it's not extortion. If the other party decides they want to pay you to not do that, it's on them and you can negotiate from there because they made the offer. If you say "I'm going public with this info on X date unless you pay me" it's extortion.