A cartoon explanation. Another cartoon explanation is espionage. If you were really concerned with planting espionage equipment, you wouldn’t cut all the cables at the same time, making a conspiracy obvious to all but the biggest dolts. You’d do it quietly, one-by-one, over time. Actually, I very much doubt that such sniffing is necessary. All that the NSA needs would already be built into the original equipment supplied to the cable laying companies, not to mention the computer equipment on dry land. An experiment – to see if it could be done undetected, to see the effects, and to see how long a fix would take – is still the best explanation.