When a child gets bitten by dog that they were pestering, why does everyone take up for the child?

The dog is only defending himself. If they dog is dangerous to begin with then the parent should keep the child away from the dog otherwise why is the dog wrong? Sure the child might not know better, but more often than not it results from the child mistreating the dog and the dog just defends himself just like we would if someone hit us or pulled our tails (if we had one). Parents need to be more responsible and stop blaming the dogs. It should be seen as a learning lesson to the child of what happends when you misbehave. I'm tired of hearing about dogs being euthanized because they bit some brat.