The answer is in your first sentence. This story speaks of a failure for sure but not a mystery - though it should be in a perfect world. I don’t know if this failure is representative of a common problem in USN engine rooms or not so not sure I’m on board with the incompetence ramping to sabotage thing but…
The connection of the fire main to the engine cooling system is probably only in the imagination of the guy who “fixed” it. A less than competent person might go down a path such as:
- Fire main pressure dropping.
- Look for open valves or leaks.
- Send out search parties, find water “gushing”  out the tell tale.
- “Fix” the leak.
Sometimes when you tell someone to find something they will find it one way or the other. A certain kind of in-duh-vidual could have just as easily found the domestic reefer SW cooling overboard and try to bung that.
Of course this story is a ludicrous perversion of marine engineering reasoning and a complete failure of experience. It is not unheard of for even a civilian crew to possibly have such a “genius” as would bung a tell tale hole even as said hole was trying to “tell” you something. BUT one would hope this is an action that would get ones hand slapped early and hard by someone who does know better. [As an aside - in the merchant version of this - typically this sort of silliness manifests as a series of gutters and troughs directing the flow to a bilge well or save-all tank. It takes a bold oiler, Q-man or even inexperienced engineer to hammer a bung in a hole on a machine without guidance from above - leadership being available and competent enough to not allow it more than likely]
For it to proceed from a foolish act to engine damage is of course a tragedy and - though I don’t know the technical USN definition - a failure of leadership.
The story the USN seems to be telling elsewhere about the LCS is how well trained the crews are on these vessels. Using VR to walk through the systems and learn them, operate them and fix them with their “avatars”. They speak of two crews alternating so they can really have experienced people always onboard and ready to go/maintain. Certainly the quality of that training and manning has to be re-examined and changed in light of what we know so far.
Is a complex VR representation of a machinery space capable of substitution for spending days/months/years on the deck plates, makers schools, reading TM’s for hours and hours? For older guys/gals teaching younger guys/gals?
Was the cost of the VR trainer worth the damage of this one incident or potentially fielding a class wide crew of equally incompetent engineers?
Many years ago I created the Kings Point Gasket Award for Engineering Excellence, these guys are definitely nominated this year.
Will there be a further report made public? Is the person interviewing the crew and performing the investigation themselves competent? Or does the investigator also have some skin in the game? I am always wary of the lessons we learn from things like this. As if now paying some VR company to go shoot film or create wire frame views to be rendered by animators (at a huge payment to some support contractor) to NOW show the tell tale hole in the underside of the pump mount/housing to be explored by the trainee IS BETTER than a few minutes staring at a pump cross section and figuring it out for yourself or having someone more experienced explain it to you.
 it’s hard to imagine the flow of water from a tell tale hole on a pump of that size even with a major seal failure passing through an orifice the size of a typical tell tale can be described as “gushing”. Use of this word suggests a cover my tracks approach to reporting to me. Plus don’t they look at things like that and a hundred others on rounds? Our most inexperienced oilers check things like that every round. Before they become “gushers”. Or don’t they make rounds?