As somebody who's spent time around absolutely batshit insane schizos on 4chan, yes, there are people who would do this kind of attack (and actually worse) for absolutely no reason. At least no reason discernible to sane people. Mass shooters and serial killers have posted on 4chan after all, and the ones that don't still end up venerated as saints on boards like /r9k/ or /pol/.
Now, that is not to say the mods and jannies are not niggerlicious faggots of the highest degree, let it not be said I defend the jannies and mods from righteous comeuppance, but the fact that this happened due to an understandable grudge with the moderators, and not due to one of 4chan's many, many schizophrenic retards going pitbull and mauling their handlers, is a matter of chance only. It's like winning the lottery for the 4chan team, honestly.