
In defence of Greyhounds they are3 amongst the genetlest dogs going, and the main reason for muzzling is as a safety precautiuon shoudl they take off after a small moving object as per their training. This could be a Cat or small dog, which could be hurt or killed in the thrill of the chase.
The incident with the puppy from what I remeber the Greyhound was lying down and grumped.sniped at the puppy, not attacked it as such. Many adult dogs are not keen on pups and witll tell them to 'buzz off' in normal canine terms., which can seem quite horrid, but the pup is never actually bitten.
My own older bitches at the moment are being quite harsh to my current litter and sending them off with a squeel when they try to get too familiar, th3eir own mother is being the same, and they are learning not to push themselves on adults unless invited.