Under Vatican law, Bishops are requried by Art 30 under Sacrementorum Sanctitatis Tutela to conceal clergy abuse unless there is a civil law requiring them to act. http://www.vatican.va/resources/resources_introd-storica_en.html 
Bishops who do not abide by the directive of canon law are threatened with excommunication. 
The Catholic Church hierarchy behaves like that of a multi national company. 
Bishops are accountable to the Pope, not the people. The Vatican has failed to act & to instruct its 5000 plus Bishops to mandatory report clergy abuse in every country it is based. The Vatican only claims to be responsible for children living in the Holy See - basically church palace. In 2014, United Nations demanded the Vatican immediately remove all clergy who are known or suspected child abusers and turn them over to authorities. A must read Barrister Geoffrey Robertson QC's  'The Case of the Pope: Vatican Accountability for Human Rights Abuse'. https://www.youtube.com/watch?v=TumKd_mhmMY