explain why the flat earth movement is only concentrated in the U.S.A?
There is a lot of people who feel lonely and abandoned in the USA.
They have been programmed and conditioned from birth to feel the need label, group and belong.
This movement offers them a sense of community and belonging especially if they are the paranoid types. i.e. sheep need to herd. It makes them feel unique and tribed maybe because they grew up longing for this.
Other countries give their citizens a better sense of belonging through various tactics and tools and fill that void to belong and tribe better than the USA.