You do not have to believe that all of the world's suffering is literally your own in order to still desire to stop all the world's suffering; I commend you if you have this
However, some people are so habitually selfish that they can never have this intrinsic respect for everybody else unless they see everybody else as themselves, and these same people, unfortunately, are almost always the most unwilling or unable to adopt this new perspective.
Plus, even with no desire to cause or allow others to suffer, people may still sometimes do so unintentionally.
This is all due to our egoic separation: the
fact that each of us is only directly aware of his or her own life. Because each of us is only directly aware of his or her own life, each of us, at least sometimes, is liable to disproportionately focus on promoting his or her own happiness
(as opposed to the happiness of others who may be in greater need) and disproportionately adhere to his or her own beliefs (as opposed to the beliefs of others who may understand better). Thus, whenever people lack empathy for each other or are ignorant
of each other's better understanding, this is because of our egoic separation, and one or both of these two factors—people's ignorance and lack of empathy—can be found, in some way, to cause and/or worsen every one of the world's problems.
Our egoic separation, then, may be illustrated like this, where the the larger brain represents those who understand better and are in greater need: