Words mean things. They form the basis of our laws.
It is legal for a private spook to be hired by private persons or corporations to spy on others. It is illegal for a spook of any flavor to be hired by the government to spy on USians without a warrant or similar device.
Your last statement is really what all the fuss is about, though -- the government is trying to contravene how most sane people would interpret the Constitution, and legalize such activities.