Aggression in Chesterfield

My brother Russell lives and works in Nottingham. He works hard and is good at his job. As a by-product of that he has some nice things including his latest acquisition  which is a Lotus Elise (male menopause?!!). I've just been chatting to him on the 'phone and he told me that he was driving to an appointment the other day in a less than salubrious area of Chesterfield and he accidentally hit a dog that ran out in front of his car. The dog was okay - got up - and ran off...but within seconds he was surrounded by 4 aggressive looking youths who then proceeded to kick the cr*p out of his car. 

It was an accident that he hit the dog - the dog was okay - so why would these people feel the need to turn all feral and start attacking him? He said that his initial instinct was to get out of the car and have a go back - but then common sense and self preservation kicked in and he drove off. Obviously he reported it to the police - two hours to make a statement - and since then he has heard nothing :(

What is the world coming to?