I think the White House suddenly decided they had to agree to this to push the VA scandal off the front page. But, I don't think they realized the amount of blow-back, and especially the outrage over the circumstances of his disappearance (and subsequent deaths while looking for him). Either they thought it wouldn't matter (which is idiotic) or they thought it wouldn't be reported by the knee-pad media. But after the information went viral, it can't be ignored.
The DoD made all the participants sign an NDA (which is unusual). Now, some of them are ignoring it. It will be interesting to see if anyone gets prosecuted.
There will be a lot of whistle blowers on this deal...