Another movie where the back story makes zero sense
The Hunger Games is the worst example of this. Panem has the tech to make hard light holograms (mutt-tations), force fields and maglev trains, but they need coal from District 12 for some reason? Its like the Capital exists solely to be the bad guys.
This movie is another. The Others have the tech to cause tsunamis, genetically engineer viruses and EMP the entire planet in one shot. Yet they go into a long involved process of capturing, brainwashing and deploying children to kill the rest of the population? Why wouldn't they just engineer another 3 or 4 diseases that bugs and birds can spread?
Even if the background doesn't really matter that much since it's an excuse to have the story wee are watching unfold, these are some really lazy examples in world-building.
Oderint Dum Metuant