Because the US has a pretty sizable naval fleet of the US Navy plus US Coast Guard, extensive surveillance capabilities due to the "war on drugs", the jurisdiction and responsibilities are relatively clear, and outside of the 12-mile zone the cables simply are too deep to be affected by anchor dragging.

In contrast, the North and Baltic sea are a hodgepodge of individual nations' 12-mile zones, the Baltic Sea operates under an entirely different set of agreements that guarantee free passage, and it's not really deep so submarine infrastructure like cables can be hit by anything from anchors to divers with explosives.