That's pretty much how I justified letting the kids play. Everything we've ever played involved killing something. From shooting turtles with fireballs and straight up shooting birds with a light gun back in the day, to killing zombies and spiders in Minecraft. Since some of my 8 year old's friends are playing COD with their older brothers, I felt the need to not be such a curmudgeon and let him play some kind of FPS...so cue Destiny with no blood or cursing, and something I can get into as well. Then of course, whatever the older one does, the younger follows.
I don't see much of a real life reaction out of them like I did when they were playing the Sonic game with the werewolf hedgehog. That game spilled into real life and made my kid angry and just an all around brute. We had to hide that disc and say we lost it.