I have had this issue discussed with me countless times. I don't initiate these discussions but the people who have initiated them have been aware of my LE and teaching backgrounds.
By far the most common rationale expressed to me is the statement 'I just could not take a human life'. That even extends into their home, the protection of their families and loved ones. I tell these people I could not disagree more, but I have found it is pointless for me to push it further. They are betting the odds will favor them and a deadly threat will never occur. They are entrenched in their emotional state.
We moved from a typical liberal Calif county where I worked, and that is where I most commonly encountered that attitude. These people, for the most part, were not anti-2A. They favored the 2A - for other people.
I seldom run into the attitude now. We now live in a rural mountain area. People here tend to be self-sufficient and that includes being armed. Sheriffs support this concept through their issuance of CCW permits. Unless a person is otherwise legally precluded from possessing a firearm, they will be able to get a permit.
Having lived in both urban and (now)rural areas, it has been my observation that overall philosophies, attitudes and thought processes differ widely. It is far more reasonable where we now live. One of the countless reasons why we do live here.
It's complicated. Growing up and living in South Dakota guns were just tools and concealed carry was just another way of using a tool. At the time concealed carry permits cost $5 and took about 3 days to get form the local sheriffs office.
When I worked in DC and lived in Arlington DC, it was much more complicated. The staff in Arlington country made it as hard as possible to get a concealed carry permit - actually violating the law in the process as northern VA was out off step with the rest of the state - but knew that growth and numbers were eventually going to be on their side)
Here in eastern NC it's much more SD like, except concealed carry permits are much more expensive to get, with additional training requirements.
When I moved here but still had to do a couple days every two weeks in DC, I had my NC application notarized at a branch of my bank in DC. I expected some anti-gun side eye comments but got exactly the opposite. The branch manager went off for about 10 minutes about the harm gun control caused in DC and how criminals came over from MD and VA to prey on DC residents that they knew were unarmed. (He wasn't wrong as crime rates in adjacent counties in DC, VA and MD confirm that.). He was extremely pro 2A.
Co workers were generally anti-gun, with a big caveat. Most regarded people who carry guns as unstable red necks. When a few found out I conceal carried that attitude didn't change, but the added "except you, you're normal". They were not entirely wrong. I am a pretty normal example of the kind of people who conceal carry. They were however wrong in assuming most individuals who conceal carry us are ignorant unstable rednecks. The majority of us who are not probably need to help the few that are present themselves a bit better.
Some of those anti gun coworkers also expressed "I could never take another human life" (ironically while often developing bad policy and regulations that did exactly that - just not to people they never personally had to meet). However, I suspect each and everyone of the, would go down fighting tooth and nail to preserve their lives and the lives of their kids if they were faced with a lethal threat. Those kind of high minded naive sentiments go out the window when a threat presents itself - assuming the person doesn't just panic and freeze.
Here in NC, I also see a large percentage of defensive handgun sales going to women, many of them minority women and or liberal, who have come to realize the police are never going to arrive in time to save them if they are threatened with assault, rape or murder. As society in general continues to become less civil and crime rates rise, the second amendment becomes an increasingly common bond.