We can argue everyday about this but no one is asking the question of "who is the person who exploited the DAO contract? Where is he? What is his motive?"
These are very simple question and yet no one has come up with an answer or at least a theory. Since you are all here and aware of the situation please express what you think.
Why would that matter ? We don't know who Satoshi is, but we can use bitcoin, can't we ? There were at least 10 different opportunities to do funny things with the DAO, so if THIS guy wouldn't have done it, the next one would. What that guy did was a normal aspect of complex smart contracts: they will not run as intended. That's normal: written code deviates from intend. People call that "bugs". If the code is the law, then the bugs are the law too. What the guy did was just illustrating an aspect of smart contracts, nothing more.
The whole question is this: can you accept that bugs are the law ? This is what the guy illustrated (and again, if it wouldn't have been Joe, it would have been Jack). If you cannot accept that bugs are the law, then you should get out of smart contracts and of ETH. If you accept that bugs are the law, then you should move to ETC. So in any case, ETH has no meaning any more.
Because there will be many more "bugs" in smart contracts.