The US is just what is always the easy selling hot topic. Unfortunately a lot of the public find themselves detached from other parts of the world because of it. We always hear about the US because the US has a huge media presence here. If CNN just did a story on xxx and no UK media has covered it yet, media companies rush to do so as it will already be trending news and will pick up readers/viewership due to American outlets already essentially marketing the stories.
Unfortunately that has lead us to get specific topic focused news often, with stories concentrating on whatever is the hot subject for the sake of obtaining returning viwers/readers previously interested in similar articles eg. terrorist related stuff, president elections.
Plenty of crazy stuff going on in other parts of the world but it just isn't guaranteed to sell.