Dogs should be killed upon the situation that happened. Even humans face the death penalty based by the situation they enacted. My sister was bit on the lip from a dog that was unable to be tamed that had cancer. The situation is always going to affect what happens to the animal.
I think dogs should not be executed for biting someone people are not killed for killing another human or animal. Its not fair and plus their a lot less dogs then there are humans. If a dog bites someone they shouldn't be killed, instead they should go through some pet training to help them to stop biting people and other animals.