And why is it "widely known" that the military has this listening system? If it's really "top secret" then no, the public shouldn't know about it. Seems like everything is "top secret" until someone wants to show off all the cool toys.
The secret bits would include what this can detect, but I guess the presumption here is that an imploding civilian sub is easier to hear than a Russian military sub. So not really giving anything away.
(The same thing happened with the snowden leaks, BTW: it was suspected for a long time that the NSA or FBI had a survellance system similar to PRISM, because it's the kind of thing that they would want to do and have the means to do, even absent any concrete evidence of its existance. The leaks just confirmed the existance undeniably and also showed how extensive it was)
As to the other points, when some top secret info does get revealed, legally or not, and the public reaction is pretty much, ehh, we already assumed that -- that seems like a pretty big failing of the whole concept of "secret." And on the other hand, I'll grant you a few exceptions, like the names of spies, position of gear or troops, perhaps the detailed weapons specs like you mentioned -- but when the name of this system is "top secret" and seemingly well over 90% of what is marked "classified" lacks any informational value whatsoever, that's a failing in the other direction, people stop caring about "secret" because so little of it is actually important.
In other words, it's widely known that the Navy has a system for listening. The internal designation, capabilities and limits of operation are not widely known and that information should be kept secret.
> The Navy asked that the specific system used not be named, citing national security concerns.