Nah, it's just the inertia of a bad idea: and a bad idea with big consequences is one of those things which is really hard for people to change their minds on. Just think, if a doctor who has testified in many of these cases were to understand that they were wrong, it would mean they would know they had contributed to the imprisoning of many innocents. It's not at all an easy task emotionally to come to terms with that, so denial is a very common outcome.