That is a good question and one that almost everyone asks at some point in their life. Current events every day tell us about people who have been harmed emotionally or physically, often as they are going about their daily tasks or jobs. Sometimes people are hurt because of their religious beliefs, their race, or just because they happened to get in the way of someone who was angry and hateful.
Even though your question is one that all of us think about, to create a good paper topic on this question would require narrowing it a bit to a particular current situation. To make a good question out of a broad idea, it can be helpful to do a Google search. For this particular question, I searched "What is the most persecuted religion today?" That would be one way to find out why some "good" people have bad things done to them. Other questions could be: "Why are so many innocent people killed by police officers?" or "Why are police officers (or soldiers, or teachers, or other people who are trying to help others) killed?, or Why are there so many bad things happening to people in Syria? The basic idea in formulating a good question for a research paper is to turn your general terms "bad people" and "good people" or "world" into something more specific.