I don't think what is being said here is that every confrontation with a criminal should end with the criminal being shot dead. But rather that should it come to it, should the individual (who was not doing anything wrong, he was not the initiator of force; that is very important. The initiator of force was the criminal) feel threatened to the level of necessitating response, that there should be proper protections built in for that individual. An individual should not be punished for protecting their rights and liberties from outside threat and force.
The simple lesson here is that if you do not want your rights infringed upon, do not infringe upon the rights of others.