Staffies are lovely, lovely dogs, but as puppies they are very bouncy and hard going. They need someone with a lot of experience and time and patience to train them good manners. An untrained staffy will not "turn" as many people believe but they will remain to be extremely bouncy, jumpy and will most likely chew things.
People take them on without realising what they are letting themselves in for.
Then there is the other side of the coin, where the numpties buy a "savage" dog who they then realise is actually nothing more than a four stone lap dog and is more likely to love a burglar to death than he is to savage to them to death and so they move on to their next "savage" dog 
There are the other numpties who breed and breed and breed without a second thought as to where the pups will end up.
A side effect of so many of them ending up in rescue (in part, simply because of over breeding meaning there are too many of them on the whole) is that people who would be the right kind of home wrongly assume that there must be something wrong with them.
Add to that to the media's unfair portrayal of them and it's a nasty, vicous, circle where the only victim is the most loyal breed of dog you could have the pleasure of meeting.
It's all very sad and I do hope Paul OGrady covers it in this show somewhat to try and help minimise all the bad press.