Indonesia had braced for a terrorist attack over Christmas - there were real concerns about the possibility of an attack. So they had a lot of troops and police out that weekend to deal with that potential threat.
I've heard plenty of reports of soldiers and police on duty going to the aid of disaster victims, but there have been some where, as in this case, they stood back. It's not clear whether they had any reason to do that, or whether some just didn't get involved.