The banned site is banned because of a history of posting anything and everything Nintendo related, right down to some random shit some guy said on some forum. Marking these posts a 'rumour' isn't enough when the rumours themselves lack credibility and plausibility.
Simply reporting this content on the front page of your website cascades. It gets reported elsewhere by other sources, and people run with it. Suddenly a simple little troll/bullshit by a random internet nobody is all over everywhere, yet still isn't any more believable or truthful.
The reason the website was banned from GAF is that staff was tired having to clean up threads and discussion based on every little 'rumour' that was posted. It's annoying when a thread gets made on a 'rumour' that originated from a guy with three posts on some obscure blog. We don't like the forum getting clogged up with any other bullshit, so this too doesn't fly.
Granted, 'banned' does not mean they can't be discussed, or even used as a source. It just means you should be very wary of doing so, as information from this source is often unreliable and inaccurate. If the banned website posts a credible rumour worthy of discussion then of course it can be used as a source, even though we block the url.
But then you've got stuff like 'Chartz, which is banned for the obvious reason.
