The lynchpin in the 'cultural appropriation' argument hinges on the idea that cultures are static. But this is a fallacy.
All culture is a lie.
There is no such thing as "Quebecois", or "American", or "Austrian".. these are inventions which require the acceptance of a conceptual lie - a non-truth - to be perpetuated - in the telling. The only way cultures persist is to keep the telling of the lie in a kind of continuum. By means of identity, differentiation and association, lies are persistent only as long as they continue to be told, identically, in a fashion which differentiates from other lies, among an agreed-upon association.
Those who would argue for cultural sanctity intend, really, to keep the lie to themselves - or at least, limit its telling to an in-group of their own choosing. In so doing, they intend to limit the mutability of the relevant culture.
Alas, lies don't persist unless you keep telling them - so cultural 'appropriation' is merely a means of controlling the identity of the culture involved within a smaller bounds of association.
I've never tried poutine, but I'd love to. The only way that can happen is if I appropriate a recipe for it, and cook it myself. As soon as I associate the recipe among others in my circle, I have appropriated the 'poutine identity' into my own identity. If I don't differentiate enough between the origin and my source of the concept, say - by sticking only to the recipe and not adding anything else, from other aspects of my identity - then the 'poutine culture' persists. But as I alter the recipe and add my own flair, perhaps by throwing some kren on top, I change the identity. Thus is the nature of lies: in order to persist, they must be continually told, as originally as possible, without alteration.
>Whats the fear?
I feel that the fear expressed by those for who cultural appropriation is unacceptable, is simply this: they lose control of the lie.
But the irony is, culture doesn't really exist as a thing until someone decides to go through the phases of identity, differentiation, and association. Thus, the culture of 'cultural appropriation' callouts is a self-defeating conundrum.
EDIT: I don't expect to get upvotes for this, because its quite clear - none of us like to think we are living a lie. It's offensive. But its interesting that the mechanism of upvote/downvote itself, is a manifestation of this fact. That you don't agree with - you invalidate, and degrade. (Downvote). That you do agree with, which you identify with, persists because you validate it (Upvote). This is the nature of culture: a system of lies kept in perpetuity, by the telling. I'm prepared for my position to disappear completely - I'm also prepared for the ideal to be appropriated without further identification. We humans have the unique ability to choose which lies we want to assist with the perpetuation, and which we wish to destroy utterly. Every culture is susceptible to this dilemma...