rat race (not a joke)

I was privileged to have witnessed a young fellow beat an 'innocent' rat to a pulp. i was bothered by this sight and stopped to probe the boy why he showed such callous attitude to the rat which happened to be outside the way of the boy i.e the rat couldn't be considered a pest to the boy because it wasn't living on the him. the poor rat was a street rat which according to my opinion is a cleaner of human wastes as such a cleaner of the environment. Enquiring from the boy reason for his deed. He said that every rat must die as they are responsible for the rat race which every human is guilty of. i was more confused than i was. imagine such a response