There's also an important point to note here - the open roads are not the place to ride "quickly". Many bikers (I was one such once) do like to 'make progress'. It's a bit of a nod and a wink. Something said to justify a form of hooning. The sort of thing that that video clip well illustrates. That biker should not be trying that sort of thing on a public road. Keep it for a track day.
The biker in the video clip was inexperienced, he wasn't trying anything stupid or reckless, he was actually quite slow for the bend and was probably trying to improve his skills. He was betrayed by the poor technique and his own body's reaction when meeting the cyclists mid-corner. It was an "oh-dear" moment that all bikers have sometimes when leaned over, but an unfortunate one that ended badly for everyone involved, including himself.
I'm not finding him excuses by any means, he surely can use some advanced training and track time. I'm also not a big fan of speeding on open roads, although one's definition of speeding could be argued easily (country lanes at NSL is pretty fast too). But please don't put all bikers in the same pot. Just as with anything else, experience is gained by practicing and leaving your comfort zone one step a time. Just as cyclists are training their bodies by pushing their limits for KOMs with every ride, for a motorbiker the ultimate goal is to master the bends - nothing more rewarding than negotiating a perfect corner.
On a different note, cycling on that stretch of road, (especially that corner) is very dangerous indeed. You will find plenty of video clips of totalled bikes and overturned cars too! As a cyclist, I would most definitely avoid the area due to high risk of collision alone.