In order for the government to take away our rights (which they desperately want to do), they need a scapegoat. Some segment of the population that they can vilify and get everyone to hate and fear. Once everyone abhors and is terrified of this segment of the population, they can pass laws that restrict everyone's freedom under the guise of "protecting" us from this group.
There are two groups in America today that serve this purpose: "pedophiles" and "terrorists." Every piece of legislation that the government uses to take away more and more of our freedom is represented by the government as "cracking down" on either "pedophiles" or "terrorists." The definitions of these two terms have been (and will continue to be) expanded to include greater and greater numbers of people, until eventually the government will be able to define them to include anyone they want.
Anyone "undesirable" for whatever reason will be labeled either a "pedophile" or a "terrorist" and locked away, and the public will be OK with it because "pedophiles" and "terrorists" deserve whatever they get, right?