Lemuel Shaw was Chief Justice of the Massachusetts Supreme Court.
Benjamin R. Curtis was a former Associate Justice of the US Supreme Court. He resigned from the Supreme Court in protest of its Dred Scott decision.
Joel Parker was professor of constitutional law at Harvard and former Chief Justice of the New Hampshire Supreme Court.
Considering the Dred Scott decision I don't see how the judges could have ruled otherwise. Taney said that blacks were due no rights at all that had to be respected, so any laws meant to protect them or grant them any rights at all was bound to be found unconstitutional.