Secrets tend to fester. They might delay consequences, but they also tend to make them worse when they do come out. They also sometimes create new ones like the niece suffered through. Her whole life she saw her uncle be loving and generous to everybody but her and not know why. Was it her? Was she seen as unworthy? What has she done? Did she deserve it? I'm sure these thoughts went through her head at least a few times growing up. She suffered through all of this because her parents did something horrible, something she has probably been raised to see as bad and to never do, and she was a product of that. She suffered and was never told why, thereby increasing the suffering because her parents were and continued to be selfish until it all came out.