
Countries can have a Lingua Franca. What is unacceptable is the intentional marginalization of minority languages. In many places, children found speaking minority languages used to be punished in schools. This happened to Native American languages, to Hawaiian, and to French in the United States. This happened to welsh, Scots, and Gaelic in Britain. This happened to Basque and Breton in France.
These posts are attempting to force people to speak English. That is different from accepting that people will naturally adopt the majority language of their country for ease of communication. And the history of this in the United States is in many ways explicitly white supremacist. Parts of this country have been speaking Spanish, French, Russian, and Native American, Polynesian, and creole languages continuously since before those areas became American.
Language is culture. Attempting to remove minority languages is a form of cultural supremacy and forced assimilation. There should be abundant access to resources to teach people English. That is simply an important part of giving people social mobility in the United States. But other languages must be fostered, encouraged, and not shamed.