That is not so much as value judgment as it is a description of the main action of each group. Negative emotions express an attempt or intention to Exclude. Strengthening one's own position at the expense of others. Keeping bad stuff away, destroying what is perceived as a threat. Negative emotions are fueled by an underlying fear of the unknown, a fear of the actions of others, and a need to control them or stop them to avoid being harmed.
Positive emotions express an attempt or an intention to Include.
Taking the whole into consideration. Working on learning more viewpoints, interacting more with others, enjoying making things better. Positive emotions are fueled by an underlying desire for enjoyment and unity. There is a range of different emotions in each category. We could say that some are more positive or negative than others.