So now people that discover exploits should be bullied and threatened by corporations for asking for more money? Heck, I hope Apple does this so that no one will ever want to use them again.
I mean, that's the station where we are heading. The moment you will come to corporation and say: "I have this and this vulnerability, black market offers me X, I want 2X from you." Corporation will then subpoena you to get the knowledge from you and then cease and desist you to prevent you from spreading that knowledge further.
You will try to threaten that you will release it to black market if they won't pay you 2X? Yeah, that's blackmailing. So what else can you do? Either you will start blackmailing them (then I hope you know what you are doing) or you will outright sell it on black market and bypass communication to company altogether.
I would hope you wouldn't threaten that and just ask for more money. If your end goal is to do that, then hopefully you'll be security conscious enough to do so and say... hm, have no idea how that got there. Me personally... I'd release it to the public and watch as the corporation suffers until the next one where they'll be glad to pay more.
