That line of thought has been tried numerous times and seems to be a consistent failure. I think that is because the person you are addressing it to has never considered the possibility of defending themself and probably never will - even if actually placed in a life-or-death situation.
Going a bit further - why do you care (OK, there is probably some altruism in play) what someone else feels about defending themself? Aren't you carrying because you want to be able to defend your self and your loved ones? Don't you believe that it is your responsibility to do whatever is possible for their safety before you even begin to deal with the safety and well-being of others? It would be nice, after assuring that you and yours are safe, if you could do something about the danger that those other folks are facing. But they have apparently decided to abrogate their responsibility for themselves and their loved ones to the hands of someone else, be it the police or you sitting two pews back from them.
The question of carry in church or anywhere else is a personal one, and I do not want to become involved in discussing, let alone debating, anyone else's decision about protecting themself. All I ask is that they not impose their decisions on me as well as themself. If it is legal for me to carry in church and I do so in a manner that does not violate the principles of the religion then I should be left alone to follow the dictates of my consience and to worship as I see fit. In other words, I probably would not be a member of The Society of Friends if I regularly carried a handgun for self defense. I'm not sure but I think the notion goes against at least one of the core principals of that religion.
Where we are at is the question of control, not the question of guns. One person wants to control how everybody behaves, and wants everybody's behavior to be like theirs. The other person wants to be allowed to decide on their own how to behave, within the restrictions of the (religious and secular) law. When asking WW$dietyD, take guns out of the question and focus on the issue of forcing others to behave and believe as you do. If memory serves me correctly, even the folks that were generally in agreement about which religion and how to practice it became "somewhat" upset over the Spanish Inquisition and the attempts to enforce a specific and rigid practice.