Why are people rude to my friend?

All through high school people accused her of lying. She lived in an abusive household, and she even chose to speak out about it. They said she was just trying to get attention, and that her parents could not have possibly abused her, and treated her sister better. I once went over to her house, and I saw with my own eyes how she was being treated. None of the teachers listened to her. Even they said that she was making it up. I myself lived in a household with abuse. I never spoke out because I was scared that I would get the same treatment as my friend.One day my friend fell and broke her leg. Everyone walked past her laughing, and saying that it was another ploy for attention. She had actually broken her leg. Her crying was not fake, and only was generous person helped her. What is wrong with society?