Progressive educator, John Dewey, thought assimilation was essential for modern nations like the United States, and a good thing:
In the olden times, the diversity of groups was largely a geographical matter. There were many societies, but each, within its own territory, was comparatively homogeneous. But with the development of commerce, transportation, intercommunication, and emigration, countries like the United States are composed of a combination of different groups with different traditional customs. It is this situation which has, perhaps more than any other one cause, forced the demand for an educational institution which shall provide something like a homogenous and balanced environment for the young. Only in this way can the centrifugal forces set up by the juxtaposition of different groups within one and the same political unit be counter-acted. The intermingling in the school of youth of different races, differing religion, and unlike customs creates for all a new and broader environment. Common subject matter accustoms all to a unity of outlook upon a broader horizon than is visible to any group while it is isolated. The assimilative force of the American public school is eloquent testimony to the efficacy of the common and balanced appeal.
Dewey, John. 1916 (1966). Democracy and Education: An Introduction to the Philosophy of Education. New York: Free Press. pp. 21–22.