Admittedly, I'm starting to wonder, but to the 'didn't show emotions' crowd....I'd say for a fact, that if my 2yo was missing, and I thought there was something I could do to help, I'd be stone f'ing cold on camera and cry my f'ing eyes out when I was helpless or couldn't be of help...whether that be getting coffee for the folks actually working the case or washing their damn shorts if that's what was needed.
I've never lost a child, and my situation probably doesn't compare, but I've been in a hospital, staring at my 6 month old hooked up to ventilators and other machines. With everyone around me telling me to go ahead and let it out and cry if I needed to. Honestly, crying didn't even enter my thoughts. She was going to be OK is what I had in my mind and therefore there was no reason to cry. I was telling myself this all while trying not to lose my ****. I'm sure on the outside I looked completely devoid of any emotion.
If they seemed gleeful in any way, I would probably be a bit suspicious. I haven't seen any interviews with them, but I would agree with you that seeming cold and harsh is probably them just trying to keep it together while at the same time, trying to think positively and not give up hope. At least that's what I hope. However this turns out, if it's bad, I pray that family was not involved in any way.