tbh I think it's a bit of a non-story.
While it is of course very traumatic for a blind person if their guide dog is attacked (have been there myself and it was horrible), one needs to consider that it's unlikely the dog doing the attacking is doing so because it is a guide dog. I.e. I'm sure there are hundreds of dogs attacked each month while on leash, it just so happens that three of them turn out to be guide dogs.
It just sounds a bit like there are dogs out there with a grudge against guide dogs/blind people when actually while of course very traumatic, it is just unfortunate that a proportion of dogs attacked each month happen to be guide dogs. By the same token I imagine some are also hearing dogs, dogs for the disabled and so on.