But when it comes to chasing bikes, I think they need to be dealt with in whatever means necessary, within reason, to protect oneself and deter them from repeating the behavior. If this causes pain to the dog, well, pain aversion can be a good thing if it means the dog stops chasing bikes. A dog chasing a biker can get in front of the bike and causer an accident, as happened to me. Fortunately just severe road rash and bruising on that one. Or the dog can cause the biker to fall into traffic, resulting insevere injury or death. Or, as happened to a dog that tore out into the road to chase a friend of mine, the behavior can result in death to the dog--it was hit by a semi passing the biker.
Owners need to control their dogs if they live by a road. With the stakes being as high as they are, I just can't get into the "don't hurt the dog" thing. Hurting the dog may teach it to change the behavior, and if the behavior doesn't change, there may be a disaster in the making for bikers, drivers, and dogs.
Again, it's not about cruelty to dogs. It's about deterrence of dangerous and irresponsible behavior.