How is stopping people from entering a geographical region "terrorism"?
If I don't let you into my property, is that "terrorism"?
A "country" is the geographical region controlled by a government. Governments are moral abominations to be sure, but despite the fact that they've build infrastructure through stolen funds doesn't make those improvements unowned. It means that the tax victims of that country are the people with the highest possible claim to that land.
Given that, those people should be able to exclude whoever they want from their rightful property, just like you'd be able to rightfully exclude people from your property. How is this "terrorism"?
RE: The Immigration Debate: Adam Kokesh vs Stefan Molyneux (Video)