I think one of your quotes should support the argument that Flusser believes that it is better to have people move between borders of countries than keeping them in.

As long as Brazilian society welcomed new waves of immigrants,… this transformation of adventure into habit and this hallowing of habit, remained charged with excitement. (p. 9)

To me, this means that there was a value from the newcomers and they added something to the culture.  At first, they added a lot of exciting things.  These new ideas became an important part of the culture.