I think we've seen quite a bit from LE that shows they haven't been just singularly focused on the parents.
The FBI, following a tip, just went to a home all the way in NY making someone prove that their child really belonged to them.
If the parents want all focus moved away from them the choice is theirs, go in and answer whatever LE needs answered until LE can rule them out completely. If anyone is keeping that from happening, if anyone is causing the case to come to a standstill, it is their defense attorneys.
JMHO
I disagree from the standpoint that they can go in there today, do everything LE asks of them, and LE still will not rule them out completely, based on the story given. There are no witnesses that can vouch for DB after she went in the house.
IMO, I also think they can go in today and do everything LE asks and that will not change certain people's perception.