It's kind of weird how people think Batman is cool with an R rating but not Supes. Its not like Batman goes around killing people. Superman has killed a couple of times(executed three kryptonians) but Batman just punches people. He's never fatal. But there's stuff in both of their books that would be r rated. Jason Todd has already been mentioned for Bats. Just showing the shit that some of his villians does could get an easy R too.With Supes it could be his fight vs Doomsday, a battle with Lobo, action comics #775, I was reading that Superman American Alien comic a couple of weeks ago and it had some pretty violent shit in it.
This would probably be rated R if it were filmed. So would this:
I don't know where this Superman is only pg shit is coming from. It doesn't matter if you like the stories or not. His comics have tread this ground literal decades ago. Both him and Batman deal with nasty people who do nasty things.