In theory, the FBI is limited to domestic operation. The DIA, CIA, NSA, DEA, etc., are charged with non-US operations.
There is no legal mechanism to tell $small_utility that they have to fix their likely expensive if ancient (must get depreciation and a long service life) equipment.
We don't have a second, fortified Internet that's immune from international traffic; it's the world wide web, not the SECURE web.
Worse, you can bet that the aforementioned agencies are far, far up the tailpipes of most Chinese infrastructure, despite much of it being newer than that in North America and the EU.
This is a game of chess, and having dormant malware waiting for action is just one more chess piece in a bigger game, and exercise for a different vector of warfare, just like the space arms race.
As you cite, finger pointing does nothing but prevent funding of active methods of helping both rich and poor utility IT infrastructure from identifying actual problems, and presenting and monitoring real remedies. Don't shoot the messengers, instead, get the politicians to agree on methods to goad the private utility sector into action; this removes at least one small piece from the chess board.