Thats what I said, these places collapsed because of nationalism.
Globalism is also inherently an evil ideology. Global cooperation is great, we want to get along with other countries, but globalism is evil, and has been tried many times before, all of it with evil and immoral outcomes. Nationalism is simply a form of pride and group identity. its generally harmless and is even beneficial.
My personal belief is that only if nationalism is used incorrectly, as in: failure to recognize shortcomings and blaming external forces, leading to social/economic failure can nationalism actually become an issue.
Also the very idea of colonialism is globalization, unite the entire world under one ruler. Austria collapsed because several major ethnicities lived in the country, and yet the country only listened to Hungarians and Austrians. They were the only represented group in the Empire. Nationalism doesnt mean that you cant work with other countries, even the most extreme examples show that even the farthest fringes of nationalism show this. The world isnt a global community, we arent all the same. We have different values and ways of thought. Globalism would require you to force one way of thinking upon the entire world, forcefully. Thats exactly what countries did when colonizing. They realized that the people in America/Africa/Asia were all different from them, they didnt eat the same food, or share the same religion, they were all different. They must subjugate them and force their ways of thinking on the people being colonized for their colonization to work, the only thing that preserved their ways of thought was nationalism, they kept their ideals at heart.