The symbols just look vaguely like anarchist symbols, and seem to love messing places up for no reason.
Anarchy is often misrepresented as chaos and unnecessary or nonsensical violence. Those are normally just trouble makers without an agenda. Anarchy is the negation of rulers and the proposal of non-hierarchical societies balancing freedom and equality. I suppose a video game reference would be the joinable factions in Planescape: Torment. "The Revolutionary League" (or the anarchists) believe all other factions are greedy liars. The "Xaositects" (Chaosmen) are crazy and, well, chaotic.