“Accurately” in this case (using a snubby at 100 yards, not necessarily a S&W 642, although it can do the job) means a hit anywhere on a B-27 silhouette target, or even a near miss that drives the other party to seek cover) is quite possible. Hold the front sight up in the notch a bit and use the head as an aiming point. The bullet’s trajectory will drop the shots into the upper torso. Focus your eye on the front sight and concentrate on sight alignment – which is critical. Get your final sight alignment just before the trigger releases the hammer.
You can do it, but the greatest roadblock is an attitude that you can’t.
Of course there are better choices in handguns for this sort of thing, but in the case of a shooting you will have to use whatever you have. Therefore you should practice to make whatever that might be as effective as possible under any circunstance.
At point-blank distance I agree with you concerning point shooting. But again a precise hit can be difficult. All the laser dot can do is confirm (up to a point) where the bullet is likely to go. An "anywhere" hit isn't good enough when you must
instantly disable an opponent to survive.
Understand that at this point in his long life the Old Fuff is no longer as good a shot as he once was. However back when revolvers were much more common then they are now, many officers qualified with snubbies that were either primary or back-up guns, over the PPC course out to 50 yards, and sometimes like I said - at twice that distance.
These cops were too dumb to know they couldn't do it.