It was outrageous to be called an enemy when you're volunteering to fight for your country, but that was compounded with the word "non-alien," which is a word that means "citizen" in the negative.
Era idignante que te llamaran enemigo, cuando estas ofreciéndote a pelear por tu país. La intención de la palabra "no-extranjero", significaba "ciudadano" pero en forma negativa.