A resposta para sua pergunta parece estar no final de Pecados do Pai , o resumo dá a essência, mas é muito melhor no episódio em si:
Embora eu suspeitasse que, após a Guerra Civil, eles provavelmente envergonhariam a família, mas Worf lidou com isso no final, à moda antiga.K'mpec says the Duras family was too powerful and to expose him would likely split the Empire and cause a civil war. In order to avoid that, they decided to use Mogh as a scapegoat, believing that Worf, since he was in Starfleet, would not challenge the judgment.