You don't have to go as far as to bring up moral relativism. As it currently stands, the US Constitution is interpreted as a series of bounds placed upon the US

You don't have to go as far as to bring up moral relativism. As it currently stands, the US Constitution is interpreted as a series of bounds placed upon the US government when it interacts with citizens. We don't have to demand that every country respect exactly those sets of bounds, we just have to restrain immigration enforcement from engaging in what would otherwise be a fairly open-and-shut case of retribution for constitutionally protected speech.