I think most anti's assumption is that we carry looking to take take life. In fact, it is the exact opposite. I carry to protect life.
I was recently asked if as a LEO I could take a life, my response, that's a choice someone else has to make. In other words the BG makes the decision to assault me or my family, I simply respond.
Conviction of character (as well as right and wrong) needs to be resolved before something happens and not after. In many counseling situations, I've discovered the folks who struggle with things had a lot of self doubt before they made the decisions they did.
My point, these are questions you need to wrestle with before you decide to carry, because once you make that decision, you have already decided you can and will take life if necessary.