Quite simply, cultural appropriation is the ressentiment of the slave morality caused by the privilege of the master morality and, simultaneously, the attempt by slave morality to attain privilege through cultural entrenchment. There are no solid arguments for the protection of culture. Historically speaking, cultures are not static entities, they evolve in interaction with each other. Most cultures that have found expression on this earth no longer exist. Native Americans in the nineteenth century, for example, appropriated all manner of western culture to the point that many lost their identities. They chose metallurgy over stone and clay, they chose to learn English and copy the laws of the west. This is not a tragedy. This is the consequence of their freedom to assimilate and the natural selection of culture. There is no basis in history for individuals feeling as if their culture cannot be "appropriated." This is a myth perpetuated by postmodern social criticism. The master morality (and the slave morality in the example just given) can appropriate anything it pleases. Its boundless freedom is of greater force and influence than the would-be restrictions of the cultural police.
No culture has the "right" to not be "harmed" by the Other. This is silly. No cultural traditions are truly "damaged" by being mocked or having aspects borrowed from a self-subscribed set of rules. There are, in fact, no cultural rights at all. Whether a culture is appropriated or not does not directly impact the culture itself, particularly among strong-willed members of that culture, and the extinction of past cultures has not come through appropriation, but rather via irrelevancy. In fact, it is a sign of strength of culture to endure the test of appropriation. It is also a sign of weakness when a culture cannot endure such a test.
God is dead and we killed him through perfectly valid appropriation and abject irrelevancy. Nothing in culture is universally sacred and there is no reason members of culture should be "protected" from how others perceive and use their culture. There is no cultural moral ethical high-ground. There is only the competition of human value judgments. This is a natural competition that transcends laws and ethics. It is a characteristic of slave morality to interject laws and ethics where they do not naturally apply.
There is no inherent reason why cultures upholding aspects of themselves as sacred, in fact, makes it so. Because, once again, God is dead and so is your right to cultural protection. What is preserved by culture is determined by the dynamic interplay of human behavior, not my some "Thou shall not commit appropriation" edict. Such a position is whimpish and naive about the way humanity actually manifests on the planet. Instead, everything is a competition of value judgments. As such, the extent to where cultural appropriation happens or doesn't happen is a matter of the exchange of power in the public sphere, not a matter of ethics and morality. History trumps ethics. Appropriation is part of who we are. So-called "progressive" sentimentality fills me and the masters of appropriation with nausea. If my baseball team wears a tomahawk on its jersey (ie. the Atlanta Braves) I don't care if it offends anyone. It is a cool logo. That is the way things actually work, human victimization be damned.