Writers are often motivated by something/someone that angers, irritates, or appalls them. Some people write to get even with a person who has hurt them, or to expose some sort of destructive force in their community. … If your story is going to be any good, you are going to have to get past this.
One thing I like to do is to write journal entries in the voices of other people, or even characters in my books. I sometimes do it for people who have hurt me deeply, so I can kind of get a grip on their behavior. The challenge is that you have to discover something new about the person or character. If your exercise reveals only what you came to the page with in the first place, then you have not tapped into the empathy you are going to need to write the story you want to write. The thing is that you are really going to have to want to understand that person, which means you may have to let go of that anger.