I don't think they are protecting anyone nor picking what to run. I think there are two factors at play. Less important but still a factor is those interviews are usually far longer than the amount of time to run them Sometimes they stretch into hours and they might only 15-20 minutes to fill them. What I really think they did is to drive up ratings at the time of the trial. Think about it, why did they wait so long and then finally release the reanacripts and did so on one of their more popular shows? They did it because of ratings, they released the transcripts while the trial is headline news.

One thing I am interested in is if NBC will turn over the transcript. I am pretty sure they do not have to by law, but in this case they may volunteer since they are not protecting a source.