It's not the arrow, it's the indian.
First rule of a gunfight: have a gun.
A .38 in hand is better than the Glock or other large auto left at home. Statistically speaking, 5-6 are plenty for defensive encounters. Revolvers work for many members here. They are proficient and accurate with them, THAT is what will end the fight quickly, not the bucket of bullets under you latest plastic fantastic wonder pistol.
I carry an airweight snub revolver most of the time and feel it's probably adequate(plus it offers certain ECQ advantages) for the vast majority of defense scenarios I'm most likely to encounter, but that's not really what is being discussed here.
Intentionally engaging an active-shooter at distance is very different than your typical civilian self-defense encounter. The shooter will most likely be armed with at least a high capacity pistol if not an assault-rifle. He very well could be wearing body armor and he will likely be suicidal, so he will not be easily deterred and will be hard to stop. The odds of such an event are so astronomically rare to be all that concerned with, but that's the topic at hand nonetheless.
"It's the Indian, not the Arrow"....
To use martial arts as an analogy- some will claim it's the fighter not the style that matters and there is obviously a great deal of truth to that, but the style also matters a great deal and those with actual experience know it. I have come across numerous traditional martial art instructors over the years who are very critical of things like mixed martial arts, force on force training and even freestyle sparring. They make bold claims about what they could or would do, but have never once proved it nor pressure-tested anything they promote. It's the same thing with shooters and gun choice and anonymous posters on Internet gun forums.
If you can shoot a double-action revolver well, I don't know why you would have problems with a striker-fired auto. I have spent a lot more time practicing with my snub revolver compared with my Glock 26, but I still shoot the Glock better and the Glock 19/17 better still.
And how do revolvers work for many members here? Demonstrating proficiency shooting static targets from a static stance at the range isn't the same as performing effectively in an actual gunfight with an active-shooter. I would expect most people's hit ratio to not be all that stellar if engaging a homicidal/suicudal AR/AK wielding assailant at longer ranges.
It's very easy to claim that you're capable of making precise shots during the chaos of a gunfight, but saying and doing are two different things. And even if you are able to put rounds into the assailant, it may take multiple hits to actually stop them if we are dealing with a determined attacker and in the case of a church shooting, I think we likely would be.
Most civilian defense scenarios are resolved by simply presenting the weapon or as soon as shots are fired. Disengagement is the goal and the bad guys usually immediately flee since there generally is nothing at stake worth shooting it out. Determined attackers are much more commonly encountered by law enforcement since there is much more at stake. If tasked with defending the church against a suicidal active-shooter, then I think you are much more likely to potentially see a dynamic similar to what's seen in police conflicts play out rather than typical civilian self-defense if an attack occurs and you should plan accordingly considering what it can take to stop a determined attacker.