Shibboleth, I have had a staff for 10 years, with two kids from new born. My kids have NEVER been bitten. Stanley my staff has never gone to bite them, me my partner or anyone. Including the postman who he rarely sees and changes often so your theory around a familiar face is bullshit.
Whilst I appreciate you are entitled to your opinion I think you need to get off your high horse and stop forcing your ideas on other people. Any dog is capable of this kind of attack, as you state in your op. These dogs are no longer bred for fighting, that is unfortunately their history.
Aorry if this offends any mods but you are effectively tarring all staff owners with the same brush. But I am certainly not a shellsuit wearing chav, I live in a respectable area, hold down a good job pay my taxes and dont live off benefits.
P.s my youngest has been bitten by a dog and required stitches. However you would be surprised to hear it wasn’t a staff it was a sharpy