The Problem was not that he killed in this situation, but stuff like jonathan kent protecting Clarks secret in very messed up ways. Dawn of justice became a Satire of mature movies. I am a fan of mature movies but not the ones just trying to be edgy. A Lot of mcu movies handeld mature stuff better than the snyder movies. If even batman gets too dark they did something wrong. Snyder getting Miller wrong for example is not helping in that matter.