You dont have to be a "hippy" to care about animals. Killing an animal is cruel, and you should be reported to the RSPCA if you do so. Same with throwing a rock or trying to run it down.
All animals have a right to live. Is it their fault they are stray? Did they ask to be put there? actually if you had the faintest idea you'd know that the overpopulation of cats is due to humans.
I cant believe the attitudes in this thread, i would have hoped people here would be smarter and more compassionate towards other living things, regardless of species.