I believe it's all very simple really and that what is at the heart of the problem is Google's wish to give precedence to trusted sites. On the face of it this is an excellent idea but the people who run a lot of these trusted sites have rubbed their hands together and put out pages targeting just about every key phrase they can think of for every product that is even remotely relevant to their key products. The result is the awful pap we are now served with, whilst real information is buried under brandspam and this update has merely increased this.
Now they need to have another algo to tackle brandspam. What will they call this? Puffin? Parrot? Pig?