US FCC to update undersea cable regulations amid suspected cable sabotage incidents — proposals include restricting Chinese companies from building cable components
US like always is missing the point. The real story should be that redundancy is key. Even with those cables cut, there was no noticeable interruption in internet services.
It says right there in the headline that their "proposals include restricting Chinese companies from building cable components." If I know anything about reading headlines and ignoring the content of the article, this means the Chinese that cables=bad. But if the cable is built in the US of A, then it'll be super high-quality. We could probably build it from fettuccini!
But on a more serious note, this just sounds like grandstanding. Most technology, even bespoke—especially bespoke—gets manufactured in multiple companies. I'm not sure it'll even be possible to preclude China from the process of making cables for us, nor do I fully understand why you'd want to. There are other ways to punish a country than hurting your own technology.
To answer your question: they'd cut it to cause harm and chaos here. But physically dragging an anchor over cables as they've been doing is different than building components. Even if they built faulty components, I'd imagine they'd fail a test before being sent to the bottom of the ocean.