"How about interviewers who bring their own biases to an interview and insist on asking the same question, slightly differently until they get what they want?"

IF they get the answer they want, then usually their line of questioning proved correct.   I don't know of the specific Couric incidents that you talk about, but I do know from working in a news studio that often the reporter will have solid information and tries to get the subject to confirm. The guest will often be evasive, but a good reporter will get to the truth.

News needs to tell a story. A good reporter has their facts and should steer the story in the direction that will tell it. You can see when a guest is either not telling the truth, holding back, or simply does not want to answer.