Many people think that having secrets is wrong, always and in every case.  Even government secrets.  I don't agree with that.  I thing there are valid reasons to keep a secret just are their are others that should not be kept.  
    An obvious example would be a priest hearing confession.  If he started revealing what people tell him, they will stop confessing.  If someone confesses to something illegal, he should encourage that person to go to the police, but it is important for the priest to keep those secrets.  The same for a lawyer hearing secrets from a client. But what about the rest of us?
    Well, if a friend tells you that they did something illegal, something major like rape or murder, than asks you to keep it a secret, you should not.  You owe it to the victims to reveal what happened if the friend refuses to confess.  On the other hand, if it's a secret that isn't about breaking the law, or is something minor like a fourteen year old admitting that he drank one of his parents beers, than you should keep the secret, especially if you promised to before the secret was revealed.
    There are also good reasons for governments to have secrets.  They spend millions, sometimes billions, developing new technology to protect the citizens of the nation and if someone than reveals those secrets to their enemies, that work is essentially lost.  And those other countries may turn that technology against you.  Some would say that is good because than it prevents countries from developing high-tech weapons, but that doesn't make any more sense than publishes a book with recipes for making bombs out of common household chemicals and believing that doing so will bring about world peace.
    In religion and spirituality, there have always been the mystic or mystery schools who's teachings were mostly secret, revealed only to trusted members who took an oath to keep them secret.  Many think that is wrong.  They don't understand that these secrets are very powerful things.  Hitler learned some of them and he nearly conquered the world with that knowledge.  That is why spiritual schools reveal only the most basic teachings publicly and keep the advanced teachings secret.

Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given.  Mathew 13:11