What exactly does this mean? It means everything and nothing at the same time. It is pure hyperbole. "Scare"..."phantoms". The use of these words assumes the worthlessness of those espousing objections without ever addressing those objections.
He could have said, "To those who claim that our using military tribunals against immigrants caught trying to help Al Quaeda or those who claim that requiring individual searches of all passengers boarding planes at the airport constitute violations of liberty, I would say that people espousing such views do not assist our efforts to stop local terrorist acts. " This would have been much less objectionable. But by using such a broad brush, he includes many people not all of whom (myself included) would side with people that oppose military tribunals for foreigners, for instance, but who otherwise disagree with the potential, and forseeable and probable, use of the Patriot Act's provisions in otherwise unrelated domestic contexts.