Why he needed to do that was never explained. Another big hit was Independence Day where a drunk, washed-up fighter pilot destroys an alien ship that is about to annihilate all resistance on Earth. The aliens apparently came to Earth to get our natural resources , a ridiculous idea if you think about it for more than two seconds. But if Hollywood tries to set an action picture in the present here and now they have a real problem. It is very hard to create a believable evil guy with a motive that makes any sort of sense.
Money makes a good motive, but is inherently limiting.
Power can be used as a motive, but only in very limited situations such as criminal suspense or government corruption movies. The one motive, which can allow a Hollywood writer to create a massive threat, is ideology. If the bad guy has a belief that forces him to behave in a certain way, and the audience accepts that, then the writer can move on to the actual action part of the story. The last thing a writer wants to do is spend 20 minutes trying to explain to the audience why the bad guy is doing what he s doing. With the collapse of Communism there is a real lack of ideologically motivated villains.