Because people are consumed with themselves. Selfishness drives every part of us. Some people have it so bad , that they can’t even comprehend that the world and its people’s are not like them. Or don’t think like them. Or live like them. They are so sheltered from abstract thought, or critical thinking , that they literally have no other idea. About anything , or anyone that isn’t rooted in self. They see the world and understand it through themselves. They can’t take off their glasses. Their self colored glasses.