If you break a confidentiality clause, you could, potentially, be putting someone's life at risk. You may not see it as that way, but you never know what kind of people are out there, and what things they can do with certain information. Not only that, but there are laws against breaking confidentiality rules, and should you break them, you should be help accountable.
Breaking a confidentiality clause should be a criminal offense, because it is akin to a breach of contract. How seriously it is punished should depend on the seriousness of the information that was leaked. This get a little dicey, though, when you begin making laws such as these. Especially when it reaches court.
Confidentiality agreements are basically contracts. The enforcement of these contracts can be settled in courts, but this is often not a jailable offense. Breaking a confidentiality agreement is necessary sometimes. If corporations or other groups are acting in a manner that threatens the public, then it should be allowable for someone to speak out about it without fear of jail. However, if there is a monetary claim involved, this can be pursued through civil courts.
There is no reason that breaking a confidentiality clause in a business contract should be considered a criminal offense. Breaking confidentiality might put a business at risk, it might mean lost profits. But neither of those things are crimes against the state or the people. It's a civil matter, for a civil court.