Most community structures have identifiable leaderships of some kind yet 4Chan has no usernames and no way of communicating provenance of a given user -- either in terms of reflecting reputation or simply being able to accurately know that two posts in a thread were by the same person/the OP/etc.
Hoaxes and stunts like this (if this is true) are either truly, truly remarkable or the work of a closer sub-set of folks who are in more private inter-communication away from 4Chan for the purposes of coordination but represent themselves to be part of the massive 4Chan community, perhaps for plausible deniability more than anything. It also makes wonderful fodder for the media to make even more of a FUD story out of.
Given that most of 4Chan does seem to be bored teenagers posting pornography, penis jokes and occasionally child pornography I'm inclined to believe it is the latter.