What this person is proposing is functionally similar to forms of anarchism and anarchist theory has some answers to these kinds of questions.
For example the communes could have a federation where representatives are sent to settle disputes. Likewise instead of a fixed 2000 people with walls between you could have people in several smaller overlapping communities which act as bridges across a network of communities. Similar to how a person can be a family member and a company employee and a resident of an apartment building etc.
Though I don’t completely buy in to everything it says, https://theanarchistlibrary.org/library/peter-gelderloos-anarchy-works goes into how anarchist communities can and have worked
Now westerners will worry when lining up for concerts or flights and the increased security expenditure will impact their economy
I guess you support ISIS terror attacks as a brilliant play too?