ORAC,
The issue is neatly summed up in para 1 from your link.
These more powerful lasers might, among other things, provide Navy surface ships with a terminal-defense capability against certain ballistic missiles, including China’s new anti-ship ballistic missile (ASBM).
Like I said, "Even the USN haven't come up with one [a solution] yet", all they have is an idea. A pretty sci fi idea at the moment.