He didn't tell anyone they were murdered. Because doing so might lead to the revelation that it was Bucky who was forced to murder them. For two years. Nobody asked him about it because he didn't allow that to be an option. And I do fully understand why, but it's still not something I can forgive him for. His reasons aren't enough to justify that in my eyes. You can't lecture other people about telling the truth and then just hide a murder. Even the implication of a murder.