Same thing with a problem family on an estate, criminality in general, the scumbag kids at schools that disrupt every lesson and every teacher wishes they'd just expel.
The difference is though that these are just dogs and we probably could be more proactive, there are protections against evictions, locking people up or expelling them etc.. so even though everyone knows that if certain kids were kicked out of a class or school it would improve things for the rest or if certain families were removed from an estate or building or certain local trouble makers were simply incarcerated then you'd solve a lot of problems we can't do that as there need to be checks and balances against that sort of thing.
With dogs on the other hand there should be literally nothing wrong with just outright banning some types (make it a broad bull terrier ban) and licensing the rest, have people lose their license if they demonstrate they can't look after a dog etc..