The problem with Fox News is their viewers. Why this is as mainstream as it is, and not some harmless public access ranting, is just an indictment of a swath of US viewers.
It works because they're stupid. It works because the network tells them their smart by exclusively watching Fox and not a variety of networks. It works because some human beings don't want to stand for anything except hating another who isn't them.
In this case Fox News allows viewers to hate, hate, hate the evil liberal, who wants to destroy America, take away your rights, and make you be an atheist depended on the government. If your morals are vacuous, and you need to find meaning by hating something or someone else, then Fox News is your bag, baby.
Don't hate the news, hate the people who watch it. It's entirely their fault.