Fake news undermines the real news.
Fake news has consequences.
Fake news hampers an informed citizenry.
Sharing fake news undermines your credibility.
If your arguments are built on bad information, it will be much more difficult for people to believe you in the future.
Fake news can hurt you, and a lot of other people.
Fake and misleading medical sites like Mercola.com and NaturalNews.com help perpetuate myths like HIV and AIDS aren't related, or that vaccines cause autism. These sites are heavily visited and their lies are dangerous.
Real news can benefit you.
If you want to buy stock in a company, you want to read accurate articles about that company so you can invest wisely. If you are planning on voting in an election, you want to read as much good information on a candidate so you can vote for the person who best represents your ideas and beliefs. Fake news will not help you make money or make the world a better place, but real news can.
You deserve the truth.
You are smart enough to make up your own mind, as long as you have the real facts in front of you. You have every right to be insulted when you read fake news!