Yeah, the 'tists on 4chan have already pointed out that the "anarchy" symbols (like who does their anarchy symbols like that?) seem to be copied from Google; the edges of the spray where it meets the brickwork looks like it was masked off - to protect the brickwork; Anybody who goes to the effort to source a pig's head should also be able to get at least a bucket of real blood to go with it; and people who tagged in a previous life said that leaving messages like that would 99% of the time come with physical damage, even if it was only the garage door panels.

So, yeah, false flag seems to be the current theory.