Any whistleblower is likely to be changed into something nasty and given everyone in the Kingdom already knows that, people will think twice about speaking out on something that at best will change their existence and at worst end it. They will think even further about publishing anything given this would be used as direct evidence of the "crime".
This overall attitude is not necessarily a good thing (the Queen thinks otherwise). Eileen has spoken out against it and is well aware her own royal status has been what has kept her alive at times. Even L'Evallier, not a keen fan of upstarts speaking out of turn, can see a point for whistleblowers to help keep the fairy government accountable. The Queen thinks it a personal insult given she really does try to serve her people - and in fairness she does.
There is no obvious solution to this and the Queen has made it clear she does not want to discuss the issue. L'Evallier, with time, will try to find a way around her attitude and show her it is in her interests to be transparent but it is a case of taking the softly, softly approach.
Any secrets/secret keeper would be protected by a curse on them. That ensures the secret keeper will not want to break it given the wide range of curses available for magical practitioners to impose on people. The really clever person will ensure that the curse will strike anyone, such as a journalist, if they try investigating secrets. The even more clever person will ensure there is nothing to give away the fact there is a secret to keep in the first place.