Money is our base vote in society. It rewards value the moment it is spent and builds cooperation. We buy things that benefit us.
Social media "likes" are an expression of opinion (agreement or disagreement). Likes reward things that grab our attention and build tribes (segmentation advertising). We spend time on things that (we think) define us.
It is easier to define what we are not than what we are. Thus, the reward of the negative on social media.