Ammunition manufacturers have made the simple complex. There's little money in a soft lead round ball and the armchair shooters are never satisfied with the simple. Automatics need hard lead or even smoother bullets to feed properly whereas as wheel guns can shoot anything.
Most policeman that I've shot with are mediocre marksmen at best, so no surprise there.
Sixguns, especially cap and ball, are natural pointers and have little need for fancy sights or high capacity magazines when their first shot is deadly enough to put down a horse, let alone a man.
To further qualify this friendly debate, we're talking civilian self-defense, an intruder coming into your home, not military combat. Most shootouts involve very few rounds fired.
At one time I had all three .40 cal Glocks (22,23,27) and carried and shot the 23 for nearly two decades. None are as comfortable to shoot and as natural pointers as a sixgun. Wouldn't you agree?
As for the comparison to cocking the hammer and flipping the safety off, you're right, both can be done while the weapon is being brought to target. The Glock has an aversion to dirt and mud and the M9 shoots wimpy bullets, make mine a GI 1911!