You whiners need to get over it. AT&T is a business and therefore it makes business decisions. When AT&T offered unlimited data, devices simply didn't use that much, they were slow, apps were slow, steaming movies and videos through cellular technology wasn't quite here yet, etc.
Now data consumption has gone through the roof and AT&T has to manage their costs. You are bunch of entitled babies that expect businesses to operate at a loss to give you the service you think you deserve. You are lucky they didn't strip away your unlimited data already. Businesses are NOT in business for the good of humanity. They are here to make a profit. They make a profit by providing goods or services at a price where we can FREELY choose to trade our hard earned dollars for that service. If you don't like the service they provide, STOP freely CHOOSING to trade your dollars for their service. It's as simple as that.