ARE WE OUR BROTHER'S [SISTER'S] KEEPER?

Recently there have been two more killings that have been justified by claims of self-defense as the shooters felt "threatened."  One threat apparently was popcorn being tossed at the shooter's face and the other based on loud music coming from a car with a number of young males in it.  Previously a man in Florida pursued a young man wearing a hooded sweatshirt and felt threatened because the hood was covering the person's head.  None of the people killed had weapons unless a box of popcorn is considered a weapon.  Does feeling threatened justify killing?  Aren't we supposed to be looking out for [caring for] other people? Are there other ways to deal with feeling threatened?  If guns don't kill people, it is people with guns that commit the vast majority of killings in the United States.  Other countries with fewer guns have many fewer deaths from guns.  

So what are we to do?  I have previously blogged about the importance of having reverence for all living things and the problem of having guns increasing significantly the risk of someone being killed.  Does the right to bear arms really mean the right to kill others because we feel threatened or does it really mean that the states have the right to have militias?  Does reverence for life only count if we don't feel threatened?  

My understanding of reverence for life is that our own lives are enhanced by caring and having respect for living things and that our lives are diminished when we do not treat living things with caring and respect.  Isn't it time that we in the United States committed ourselves to having reverence for the living and stop having reverence for guns?