I would be astounded if John Walsh was not sympathetic to the McCanns. However, John Walsh's opinion does not constitute a kind of universal stamp of approval for the McCanns.
The show cannot be a refreshing show of reality because we do not know what the "reality" is for that night. We have what we were told by various people there, which is conflicting. We have what people believe they saw or did, which is not necessarily true, even if it is what they believe to be true. And we have perception or opinion coloring the way people interpret the events of that evening as well.