There was a time in this land, before we were the United States of America that british troops could come into your home, take your property without cause or provocation. In many countries around the globe, that can still happen.
But, in America we are protected by the fourth amendment to the constitution which specifically guards against unreasonable search and seizures and requires a warrant from a judge based on probable cause that you committed a crime. Getting a judge to issue a warrant to search everybody without probable cause is a direct violation of the 4th amendment. When they take your emails, photos, etc. and store them they are seizing property without cause.
If you are one of those people who says, "Well I don`t care if they look at my stuff, I`m not doing anything wrong." Remember this, they will have all your information compiled just in case, so if you or someone you know does something wrong, they can go back and pull your file. They would also have the ability to find embarrassing information or activities to hold over your head.
That`s what they do in oppressive and totalitarian governments, its not supposed to happen here, it is what our country is founded on. If we are no going to follow the constitution we should tear it up. So now that you know, are you still okay with it?