Almost everybody will eventually die from one of this laundry list of items if they get old enough, regardless of where they live.
And regarding reporting, how many times can you write the same thing "american's are fat"? Or are you supposed to cover every heart attack on a news story?
Whereas murders and school shootings and such, can each have their own, big or small story.
At worst, the US has like 2x the obesity rate (and related deaths) compared to a place like Germany or France. But there's hardly any scarcity of news reports around health issues like obesity, or cancer either. Health coverage, health scares, health influencing, health fads, health supplements, diets, etc, are a trillion dollar industry.
Not all countries have such big homicide rates - most western countries have like 1/5th or less. And in most western countries a "school shooting" is nothing a person should even have to think or plan about, and schools don't ever need metal detectors, or to have to plan around such things.