It sounds like you're just skeptical of a powerful centralized state, and it's coming out through the lens of historical American federation/republicanism. That isn't wrong, but it's as much a history of competing factions as it is an strong intellectual basis.
You're not the only one skeptical of a powerful, centralized state. Try reading Kropotkin or Luxemburg. You might find the ideas resonate with you. Those authors have a coherent ideological basis, and suggest paths to decentralized democracy that has been realized in various forms in recent history, but is radically different to the current American government.
It's huge! The power to drive international trade and warfare, for starters! Also, the ability to create laws that don't reflect people in your area/community.
Also wrt this thread, states don't (generally) enforce searches at their borders, because states aren't fighting for domination with nation-states. States are only trying to control their geographic area.
Thank you for the references, I'll check them out.
It saddens me that we think of federal governments as benign protectors of our rights. The States did not need and did not want a federal government. We feared they couldn't protect our interests. We had to be persuaded through the Bill of Rights to accept their "protection." The feds have some idealistic people within their organizations, but their stance is to utilize state-level resources for their own needs, such as international warfare wealth accumulation. This includes domination of individuals. We have only our states and the Bill of Rights to protects us from the feds.
Computers represent a very real threat to federal power. People could use them to rise up against federal governments and make their lives very uncomfortable, which is to say, much like our own. These dreams of small groups contacting one another and creating world peace beginning through networked communication were made explicit in the 90s and early 2000s. The maintain its dominion, international governments from around the world simply have to assert themselves in every aspect of our lives. With state protections, one of the key places feds can insert themselves is at borders, where reaching out to people from other nation-states happens.
Efficiency is for little people, like you and me. Federal governments print the paychecks for the border patrol, tax they money the pay them, then tax the people the border patrol buys all their worldly possessions. They care about efficiency less than google cares about disk space. I know I sound like a paranoid libertarian here, but I'm actually only a slightly-light-of-center person trying to bring a little reality and clarity to the situation. We are essentially pets.