Let’s leave aside this “imagined communities” stuff. I think that is a childish nonsense thesis based on ignorance of the situation. The issue is that a break with the instincts is achieved. Laws come in producing homogeneity of feeling for the “Ich”, each one comes to be their own, the “Du” is set aside as something secondary. A third stage opens up, it is called by Kant freedom. We make a decision to the third stage. The issue of the Volk, as against Universal Human Beings, is a question for freedom. This has to do with the question of different “prejudices” as Nietzsche called them, which suit different so-called cultures. The same prejudices don’t suit all the people on the earth in the same way, so the Nation, the Volkisch, is a reasonable answer, not merely a chauvinistic preference of a jingoistic “nationalist”.
That would only be so if the laws were made arbitrarily. The laws are parallel to the “radical control” of nature. But, here, we are speaking of a third stage, an impersonal “radical control”, but not by nature or law.
That’s not a question of Principle. It’s not sufficient to discredit the Catholic Church that the Borgia Popes were corrupt. Or, the Jacobians that the revolution devoured its children during the Terror.
Every society strictly enforces behavioral prohibitions in a way that feels like “radical control” to whoever does not agree. One can say only that in some societies one can be legally charged or even killed for disagreeing. But, this is true in the Liberal Societies too, think of those who favour ISIS, or a few generations ago, the Soviet Union. The question of what is a reasonable prohibition, and what is oppression, is relative to the regime and the character of the citizens.
This links up to Kantian freedom, which has to be reinterpreted because of the existence of the cultures. One can review the statement of the American Anthropology Association opposing Universal Human Rights. Ergo, opposing the belief in summa ratio, perfect and universal reason.