It's totally bonkers that soldiers are alright with killing hundreds of thousands of people and destroying whole cities without even flinching.
It's worth noting psychiatric casualties for bomber crews, for the Allies at least, were sky-high with about a quarter of those not killed in combat being discharged for mental breakdowns. Whether that rate of breakdown is from the extreme risk, or from sometimes coming back smelling like burning flesh, is up for debate.
We really do a disservice when we try to take WWII and put it into a modern relativistic historical analysis. The scope of evil and sacrifice here is completely different from our western conception of War as a video game where kids fly drones and random pixels die.