Sealed adoption records, secrets, and lies keep me from knowing my siblings and them from knowing I exist. My biological parents have a right to their privacy, meaning if they don't want a relationship with me fine, but NOT the right to lie to their children about my existence and request to know them!
When a HC parent can't win in court, they turn the kids into weapons against the other parent. Feeding them lies about the other parent and step parent in hopes that the kids won't want to be with the other parent. This is child abuse. Don't be that parent.