Sometimes giving the public actual information just leads to more or a greater ferocity of "rumors, conspiracy theories, anxiety and a disgruntled public".
They might be following the Golden Rule?
"If you can't say something nice, don't say nothin' at all"
I think you are right that there is a certain percentage of the population - here and anywhere (think conspiracy theorists) - that are going to be disgruntled about *any* statement. OTOH, if information is clear, honest, and lends the impression that problems are being dealt with responsibly, it should be reassuring for most people. What they need to explain is that there's plan, it's realistic, and it's being handled as the utmost priority of responsible, qualified adults.
I think the 'legacy' of BFL weighs heavily here. As the great George Bush said, "There's an old saying in Tennessee — I know it's in Texas, probably in Tennessee — that says, fool me once, shame on — shame on you. Fool me — you can't get fooled again."