Are you trying to say that biology is the root cause? The content is successful as it emits a reaction from us. Whether a good reaction or a bad one, we still engage with it. Whether you're binge watching a TV show you love or hate scrolling a subreddit that makes you angry, the content is designed to elicit some form of reaction that keeps you coming back or memetically passing it on.
However that is not a new development in our biology, we've always been that way. It's just that we're exploiting those aspects of ourselves more and more. Weaponising it to extract as much profit as possible.
You could go another way, I guess, and say that capitalism is the root cause as "profit at any cost" allows the justification of these actions.