What nearly everyone seems to be unaware of is that there are more Chans than just 4chan. Many of "Anonymous" come from SomethingAwful.com, as well as Ebaums World, and any one of the hundreds of other chans.
Really, there's more than 4 chan.
Here's a very incomplete list of Chans. [http://shii.org/2ch/]
4Chan's /b/ is just the most visible, most famous web location that individuals of "Anonymous" frequent.
420chan's /i/, or Invasion, specializes on taking requests for targets of cyber attacks, and was the motivating force behind the DDoS attack against Scientology, along with agitators from Ebaum's World. 4Chan just bandwagoned, but since it gets over 1,000,000 unique user visits per day, it's part of the attack got much much more attention.
Anonymous isn't some sort of organized group, all black-hat hacker elite just waiting for someone to come along and piss them off. And anonymous can be motivated to do good things as well.
The cases of Trey Burba, and "Wolfie," can be seen as proof that "anonymous" can be more than some unruly mob waging war on anyone who crosses them.
So really, the author of the BBC article is just rabble-rousing to try and get Anonymous to respond.