The problem with your response that $15,000 for 30 exploits is basically nothing between two people. A given browser exploit for IE supposedly has a street value of $10,000. Assuming FireFox exploits are about the same in price, they make 20x by holding them back from MoFo.
Not to mention that they have jobs. Well at least Mischa Spiegelmock does. Maybe he will change his mind after Six Apart fires him. I can't imagine any business trusting a company that knowingly employs blackhat hackers.