The old adage "If it bleeds, it leads" is so true.
Something shocking captures our attention. Partly we want to stay informed, but also we want to feel a sigh of relief that "Phew! That didn't happen to us!"
I think humans have a natural tendency to focus on the negative as part of an old biological survival instinct. We need to make sure that shape up ahead isn't a lion about to pounce and eat us. So, since our minds are already on the negative track, so to speak, it's easy to get attracted by negative news.
I also think there is a big element of how we have allowed our society to evolve: how many times have you bought a newspaper or watched all the way to the end of the news to read/see the headline news (that is usually traumatic in some way).
If we chose to not buy that paper, then by the basic economic principle of supply and demand, the paper would start choosing different headline stories. For the TV news, write or call them.
There are metrics for how many viewers/listeners/readers a single letter or phone call represents. If more people contacted the news companies and asked for more wholesome stories, it would send the message that a trend of people wanting wholesome stories is rising.
As a friend once told me, we can choose to water the tree of positive or negative. That choice manifests in what we think about and what we do - including what news we choose to consume.
For anyone who isn't willing to give up the news entirely because he/she feels a need to stay in touch, ask yourself if you are skimming the news or if you are immersing yourself in it - and what is it doing for you?