Keeping secrets in a family

Is it unethical to let the person who has kept the secret know that you know the secret? This is a secret that has been carried for over thirty years and affected two siblings in a family of four siblings. Tonight I let her know and the response was extremely defensive. Perhaps I should have allowed the abuse of silence to continue.

My family has secrets too, and I'd like to inform some people, but that would be difficult, also. 1st secret: I now my mother was sexually abused by her dad. I know by putting dots together after decades of information and observation. 2nd secret: The fact that my mother was abused, led her to sexually abuse her 3 children, of which I was the third. 3rd secret. The abuse really messed up my older brother and sister. 4th secret. My abuse was not as harsh, it was my mother exposing herself in front of me. That did not affect me as much as what I think was heavier sexual abuse of my older two siblings. 5th secret. I realize now my older brother and sister have been coming after me since I was a kid, because, I was not treated as roughly as they were. 6th. They have basically been trying to destroy me. Only after a more serious such venture by them against me some 25 years ago was there no way I could have anything to do with either of them, that I was able to escape their clutches. I now know their thinking and why they think that. I would love to inform somebody of this, but I can't. I dream of a way that I could, but it will probably never happen, because I'm not in contact with the person I would like to tell. So, I know what you're going through. If the secret has affected 2 of 4 siblings in a family, there could be a reason to expose the secret, to protect present and future generations. What is the "abuse of silence" that you speak of? I also know of another secret from another family. I know that this individual's mother almost got her killed, because of a four year plan to get her hurt. I don't need to tell that, because the individual involved has the same information that I do, and knows that her mother is a monster, but doesn't want to say that to someone who is outside the family. You are in a pickle. If there is a chance someone could get hurt by the secret being kept, the temptation could be to get it all out in the open. But most people don't handle such things very well, which can cause a lot of problems.