As someone who experiences a degree of multiplicity, I can tell you that there are benefits to feeling what someone else is feeling.
If one of my selves is hurting or very much against doing something, I reason with them and try to help them feel better. Sometimes it works, but sometimes I wind up needing a self-care day. When one part of me is affected, it affects my whole being. When I help that one part, I am helping myself too.
I think in society, we are kept divided on issues so that it inhibits our ability to empathize with other people.
Institutionalized racism keeps us divided into groups. Religious extremists keep us divided by terror. Political parties keep us divided on policies. The media hyper focuses on all of the things that keep us divided.
People forget that we’re all co-creators of our society and we forget that suffering affects us all. Because the ability to empathize is inhibited through division, a person is more likely to only think of themself. This thinking pattern is reinforced through mass consumerism, promoting more division through haves and have-nots and also distracting people with material gains to keep the social machine profitable for the rich.
So there you go. Empathy is important to the wellbeing of society and the promotion of fear and division prevents us from working together to make things better for ourselves. We all suffer needlessly because of it.