There is an assumption being used by these companies, and Twitter generally, that I disagree with: "Once someone has behaved in a certain way, they can never be trusted not to behave in that way again".
Try thinking about it with Noah replaced by one of HN’s favorite ‘bad guys’. Facebook periodically puts out statements saying “Oops, sorry, but don’t worry – we totally respect privacy now”. How long would it take for you to believe that Facebook had really changed? How would you feel about a privacy conference accepting sponsorship from Facebook, and justifying this decision by pointing to one of the apologetic statements?