“Why the information blackout?”
First, it was on a military installation, so to have a pretty effective blackout, the Military chain of command simply has to order the people there not to divulge any information to anyone.
Second, the facts may well conflict with the agenda that this administration wants to push. We have seen it over and over and over. If the facts are unfavorable to the administration, they hide the facts.
I choose #2, aided and abetted by #1 (with orders from way, way above).