He didn't accept the evidence. He called it circumstantial. That was the point of Ann's comment. She confronted him about NOT accepting the evidence.
Why can't you see that?
He accepted the evidence. What he did was point out that the legal case presented against Coplon at the time was circumstantial. That evidence presented in court did not include the cables, although Ann Coulter, in order to score points, leads her reader to believe that it did. IOW, she lied.