I agree, you see this a lot. We hear about some offenders being difficult and abusive people but many can compartmentalize and are sweet to their own families. If you lived 20 years and every experience you had with your dad, day in and day out, was positive and loving - it is very hard to think that same person could be a monster. It is easy for us because we come in after the crime is committed and look with a critical lens. But when you have a genuine attachment, it is hard to sever that. In some people denial takes over as a defense mechanism - it is easier to believe the unbelievable than think your loved one is evil. As long as they do not interfere with the investigation or prosecution I try to ignore any family because there's no real good answer for them. Human emotions are too complicated.