Terrorism is when people use terror for political purposes. While it is often synonymous with crime, the "terror" part is rather critical. Most often, the terror is over the target's personal safety, or that of the target's loved ones.

Having an undersea cable cut does not terrify a sane person without extenuating circumstances. Therefore it may be an act of war, but it is not terrorism in the slightest.

Redefining "terrorism" for the purposes of treating lesser criminals under harsh terrorism laws is unethical, immoral, unjust, and downright awful.