The article below includes the statement :- ""The number of injuries from dog bites has been increasing in recent years. Between 1998 and 2018, hospital admissions for dog-related injuries doubled in England, with about 8,000 people admitted each year.""
There are a lot more dogs about. Not all of them have been trained to behave well. However, I think this was a rare incident where something caused the dogs to become over excited and uncontrollable.