Bob thinks borders are obsolete because info and trade can pass through them "instantaneously". (Never mind Bob's stupid notion about trade being an "instant" process- until teleporters are invented, trading goods will always take a goodly amount of effort and/or time. ) The fact of the matter is, at no time in modern human history has open borders ever been seen as a good thing. Even during ages of exploration, the first thing settlers would do when they got to a region was divvy it up into sections (owned either by families, clans, ethnic groups or later on, nations.) Knowing what is yours, what areas you have a right to farm or hunt on, or which warlord/government you'll be paying protection money to - these things are important. Property Rights guarantee you'll have a stake in the upkeep and protection of the land. If you don't own the land you live/farm/work on, then you won't care what happens to it. If you don't believe me, go to some Section 8 housing in Detroit sometime, and see how much the people living in those projects care about the buildings they dwell in. A global world is a world full of rootless, small-souled bugmen who move every 3-5 years, putting down no roots and forging no lasting friendships. The world is a buffet of experiences, every culture is distilled to an art style and a cuisine, and every relationship is transactional, ready to end as soon as one or more partners tire of the thing. Life means nothing in such a world, because no one has anything to gain or lose. Nothing is permanent.
That's the best case scenario. The worst case scenario is: America throws its doors open and it gets looted like a Korean grocery store during a hurricane. America is rich now compared to the rest of the world because it has policies that prioritize the welfare of its own citizens. Our borders create a tight labor market that force American employers to pay American workers decent wages. We generate so much wealth that we can afford to send aid to other countries. But open America's borders, destroy its labor market and force its citizens to pay for the upkeep of its new and myriad "visitors" and soon, America will be as poor as the rest of the world. Americans themselves will soon be outbred by their conquerers, who will impose their cultural mores on everyone living in the geographical location that was once known as "America". Already, in Europe (where open borders has been a thing for awhile), there are no-go zones where Sharia is the law of the land.
In short, Movie Bob wants to turn America into Malmo, Sweden, and he wants to see the same disasters that have been visited upon that place, to be visited upon you. He wants Heritage America to die, and our manufacturing base moved to dictatorial countries like China so that the US won't be able to resist the process of Globalization. Bob naturally thinks that his position in life will be raised by this process, because he's willing to help his new ant overlords round up American citizens to toil in their sugar caves.