I suspect all new frontiers are like this. There was probably a similar outcry over violence in films. And maybe violence in fictional books too. Both long lost from living memory.

It does feel different in a video game, because you're the one pulling the trigger. I played that CoD mission when the game came out, and I felt a bit sick in my stomach playing that mission out. But I'd probably have exactly the same feeling from violence in films if I wasn't so desensitised to it after growing up watching american movies and tv shows.

Its just new.