I get that. But the fact that even the .50 cal that guy was unloading was doing absolutely no damage to the Batmobile. If Batman was in grave danger, I would understand but he didn't NEED to kill him or the thugs driving those other cars. That's the difference. He had the tactical, technological and firepower advantage over his opposition and he still chose to kill. To me, something is very Punisher-like to that approach.
Fair enough.
Regarding the tone, just thinking about some of my absolute favorite films of all time; The Empire Strikes Back, ALIENS, LOTR, I notice that they really are dark and depressing movies where 90% of them are things just going terribly wrong for the heroes but then they somehow pull through and have these amazing bonds that were forged in the darkness. I felt that with Bruce, Clark, and to a lesser extent Diana in this movie. Obviously I can't rank BvS as higher as those other films with regard to quality but tonally it struck exactly the right chord with me.