Diversity plus Proximity equals War. That is the inevitable result of reading the histories of current and historic nations, their interactions with other nations, their migrations (which always result in war), and their interactions. (It's always one of the knocks on cities; it brought aliens and foreigners into close proximity, which is where a lot of crime stems from, as the closer the proximity the faster the war comes.) The last few iterations of Empire's enforcer institutions, based around a dyscivic secular cult now (again) known as "Progressiveism", has many in the West enthralled with their illusions and thus unseeing of reality.
What others before me have, in other words, argued is that this world cannot be "perfected". It is already as good as it will ever get. Therefore, the wise and smart of Mankind will recognize this and work in harmony with it instead of vainly reenacting the tragic hubris of the past. Empire (as I call it) thwarts these wise and smart folks because it can always use a severe disparity of knowledge and technique to recreate its ruinous rule.
A world consisting of nations, in nation-states, run explicitly by nationalists for their nations is the sole path to as peaceful a world as it will get by the hand of Mankind. This is the one true Civilization. (More than that requires divine intervention, something beyond Man's power to build or compel.) In order to get that world, we who would be nationalists must defeat the aforementioned disparity. The Internet allows this, and even compels it, which is why the thralls who prefer the chaos and tyranny of Empire to the lawful order of Civilization. Why?
As neighbors, we can and do talk directly to one-another. We won't agree on everything, but we can agree that we should be free to live among our own kind, in our own land, and be left to mind our own affairs. We will build and maintain our fences--as good neighbors should--and otherwise control our affairs to fulfill our own interests. That is what being a nationalist is. It's not Utopia; there will be disputes, fights, even wars as not all disputes can be solved peacefully or to mutual satisfaction. But, by reducing Proximity to a minimum we can keep it to that which is truly unavoidable for economic reasons.
And that, quite frankly, is good enough.