Flip's answer is spot-on. Just wanted to note some of my thoughts.
The conditions in places like Ferguson are more likely the result of unprecedented changes throughout the world and represent a much more significant burden or obstacle to the maintenance/progression of state power and influence. I mean, really now, the last twenty years or so have brought about massive economic collapse, resource depletion, a massive wave evictions and foreclosures, the widespread use of social media and cellular technologies, as well a wave of growing global civil unrest.... nah it's them outside agitators, right?
Given this, one can see just how vulnerable the state is to a growing influence of anarchist ideas rather than the physical proximity or actual participation of "white anarchist". Shallow debates over such cliches also serve as thinly veiled attempt to drown out, distract, or silence any such discussions. Ironically, the strategy could backfire perhaps in places where anarchists have no significant social or intellectual influence, even if negatively drawing attention to it, this can still spark curiosity among those otherwise not exposed to, or influenced by these concepts.
The question on property "destruction"(?) seems strangely (miss)leading to me in that it locates it as some kind of ultimate goal or a political identity marker. What does it mean to "support" something like that? Also, who has compiled all the information on all the masked people looting and burning in Ferguson? Did the cops miraculously catch every single one of them and publish stats about their resident address', race, and political ideology? If so are we just supposed to take that all at face value or is there an unbiased study of those demographics somewhere?
What is a "cause" and what does it mean to "own" it? Does it mean the suppression of ideas in defense of the state. Does that suggest or advocate for some sort of racial essentialism?
*Minor edit for grammar and emphasis.