It's not just the fact that they were compromised--it's that, by being compromised, the attacker(s) had access to so much disparate data and infrastructure. Basic network design: you separate the various areas of your network, keeping more sensitive data in more secure locations. Anything potentially facing the outside world should be locked up tight.
I'm not saying it's possible for Sony to have ever been 100% immune to this kind of breach, but given the timeline and the amount of data that was taken, it's pretty clear that once the attacker(s) got in, they had access to damn near everything. This means whatever trust system was in place was fundamentally broken.
The fact that Sony is having to completely rebuild the PSN speaks to the fact that their infrastructure was flawed beyond repair. It's unfortunate that they had to suffer an attack of this magnitude in order to get their shit together, and even more unfortunate for their customers, who no doubt trusted Sony to be responsible in the first place.
Are you aware a hacker published the keys to his hacker buddies so they could do all of this to Sony's systems? It's not like Sony built a system with the doors left wide open so anybody could do this. What happened is cyber terrorism and are now being tracked by the FBI. How can you blame Sony for what the FBI themselves are labeling a terrorist activity? Blaming Sony without the full picture is the exact mentality the hackers have. Why would you even assume one of the top electronic corporations in the world would have poor security and question the ability of the hackers?
The relationship between the master key George Hotz released and the PSN breach is tenuous and has not been confirmed in any official capacity. There is
speculation that the the master key was used to sign custom firmware designed for developer-level access to PSN, which is believed to be how the breach originally started. I have not, however, seen any confirmation of this and it still remains just that--speculation.
So, let's say that Sony, by default, trusts developer PS3s to have unfettered access to PSN. This is not a great idea but not unforgivable on its own. There is still no reason--
no reason whatsoever--that a developer PS3 should have access to any personally-identifiable information regarding PSN users. A minimal amount of data might make sense, such as usernames and other data to permit testing of PSN features, but credit card information? Home addresses? Email addresses? Real names? Hell no. There is no reason developers would need access to live information of that nature and Sony was reckless in not having it secured. What if someone had simply
stolen a developer PS3 and figured out how to do this, or a developer with a chip on his shoulder decided to go rogue? The consequences would be the same, key or no key.
At issue is not the legality of what happened--clearly, the attacker(s) have grossly violated the law and deserve to be prosecuted to the fullest extent. This does not, however, excuse Sony's evidently inadequate and scattershot security model.
Sony's moves to save face and rebuild the network are just closing the barn door after the horses have escaped. The damage is done and I'm not convinced Sony was diligent enough in protecting its users' information. Like it or not, businesses that obtain such personal information are
legally obligated to take certain measures to protect it, precisely because of instances like this.