In their defense...in addition to posting about the ransom note...they have said the police made accusative noises toward them immediately and as time went on it got worse. I'm certain the Ramseys had a lawyer already to handle their business affairs, and I'd bet that lawyer told them in no uncertain terms to get legal help.
You're entitled to your suspicions...I used to think exactly your way but not so much now. I'm open to other ways of looking at it, whereas way back then my suspicions were on THEM.
I'm open to an intruder, just not a random psycho the Ramseys had no knowledge of. If I had LE talking to me like I'm the suspect, I'd give them whatever they needed until their suspicions eased and then I'd be on their ass about finding the real killer. I'd take the chance that they'd find something incriminating, confident that I had done nothing wrong. I'd take any open microphone and filibuster the point that I had done nothing wrong and redirected the conversation towards finding the killer. Parents with half of John Ramsey's IQ do that everyday in the media. 90% of the people watching/listening are going to instantly side with the grieving parents.
Everyone grieves in their own way but I know I wouldn't drag out the first few critical months of a murder investigation playing hide-and-seek with the cops. The police, from experience, are right to initially suspect family members. Acknowledge that but then convince them this isn't one of those cases - unless, of course, you have something to hide.