I've known since I was in my pre-teen years that I have the capacity to kill. I also have the ability to live with it. That said, I have chosen to follow the laws of the land wherever I may be. I have made the personal choice not to kill that which I know is endangered. Not to kill that which is out of season or illegal. I also will not waste edible meat from what are considered game animals.
If the rules change and I need to eat or to protect myself, family, or property... Or there is some plague of varmints.... Then I have the ability to do what it takes and live with it. I might shoot a varmint or two just for fun now.
Of course, this may not always mean using a firearm.
"If someone has a gun and is trying to kill you, it would be reasonable to shoot back with your own gun." The Dalai Llama (5/15/01, The Seattle Times)
"That rifle on the wall of the labourer's cottage or working class flat is the symbol of democracy. It is our job to see that it stays there." George Orwell