Everyone does not try to find something wrong with good people. However, many people try to find something wrong with good people, and that attracts attention. Some people will think that a person is not good because they have different political and religious beliefs, different skin color, or some noticeable imperfection.
Furthermore, some people who are often revered as good people, turn out not to be so good because of some secret they have kept or something they failed to do.
Thus, it becomes a matter of trust. Unfortunately, some people are untrustworthy and many people just do not believe that there can be good people, be it the man who works, never cheats on his wife, provides for his family and attends church every Sunday, or the elected official, who admits he had an affair with his secretary while on a trip paid for with public funds. Since we are not perfect, someone can always find something wrong with "good people."