it is NOT to stop people from running game with hounds. it is to prevent the harassment of deer, elk and other game from dogs left to their own devices.
about 3 or 4 years ago there were two dogs in the area of the Aspen hospital that were harassing a yearling cow elk. they were large breed dogs and by the time the DOW officer got there, the two dogs had opened up the belly of the cow elk. the officer shot the two dogs, he was quoted in the paper as saying that the only reason he did not cite the owners of the dogs for illegal take of an elk, is because he killed the dogs. but he could have cited them anyway. i know the officer, he is a good guy and would not have killed the dogs if he did not need to.
there are people all over this more and more liberal state that let their dogs run. in the months of december, january, and february, the deer are very vulnerable. the weather is sometimes brutally cold, their food is buried in the snow, and a dog harassing them often times means a slow and lingering death.
i spend a great amount of time hunting coyotes in the wintering range of deer, which also happens to be near houses. i have seen dogs chasing deer, i have seen dogs eating dead deer, and i have had dogs come at me while they were defending their kill.
there is also the ranching industry, if a dog is out harassing livestock, they can and should be shot. i hunt on quite a bit of land owned by cattle ranchers. they are VERY happy when i take out a domestic dog that is out on the property, and most tell me to shoot any dog that is not theirs when they grant me permission.
the law is NOT outdated, it is needed more now than ever. i was just up scouting for deer yesterday. i was near the trail that goes up over Maroon Pass. i was about 800 yards from a doe with 3 fawns, the trail was about 200 yards from me and 600 yards from the doe. a couple was coming down the trail with 2 dogs, one unleashed (illegal). the doe was focused on them for several minutes until they passed. it stresses the animals when they see a predator. they do not know the difference between a coyote and a dog not on a leash. all they know is it is something that is a threat.
if you are in colorado and see a dog out harassing wildlife or livestock, shoot it. the laws against letting dogs run and dogs harassing animals are not enough deterrent to people letting their dogs run.