"If it bleeds, it leads" is older than society. A news org can put out a perfect spread of articles that cover a whole spectrum of positive to negative, and social media and normal human beings will only attract to and focus on the negative. Social media has been enhancing that effect, because they figured out that rage bait is more effective than even the most positive message you can come up with, because we are animals.

If you want to maximize "Engagement", which these companies explicitly do, then you WILL maximize rage and doom and gloom. They drive engagement more than anything else.