Maybe they kept it quiet to not reveal the satellite was still operational? I doubt it given the current situation, mostly likely it'd be all over telegram and we'd have known about it.
> The Navy began listening for the Titan almost as soon as the sub lost communications, according to a U.S. defense official. Shortly after its disappearance, the U.S. system detected what it suspected was the sound of an implosion near the debris site discovered Thursday and reported its findings to the commander on site, U.S. defense officials said.
Instead they leaked it once the debris was found?
As for why they revealed their foreknowledge now? I don't speak for the military, but admitting to it vaguely, well after the fact is a significantly different situation than talking about it at the time and making it actionable intelligence. Furthermore, something may have leaked to a journalist, who then pressed them to make some kind of answer.
What conclusions would you draw?
Let's assume that in our current reality, U.S. agencies did not detect an anomalous sound. So what we've observed is how they would operate if they had zero foreknowledge or data other than the initial report to the Coast Guard.
Now imagine the alternate scenario in which Navy or NOAA buoys pick up a suspicious sound near the Titanic. There might be a flurry of U.S. gov activity (e.g. communication between NOAA, the military, and intelligence agencies) to make sure it's not a Russian sub, but that would be completely hidden to the public, and for all we know, is something that happens relatively routinely.
In this alternate scenario, what would change about how the Navy, Coast Guard, or any other U.S. official has responded? Coast Guard rescue ships would still conduct search-and-rescue, the Navy would still send a deep sea salvage ship. You honestly think the Navy would volunteer information about an intelligence report that, as far as they know, may or may not be related to a now-missing civilian sub?