I’ve seen this mentality a lot in certain circles and frankly, I disagree. This ignores the fact that children and adults consume media differently. Adults can handle certain nuances that children can’t. Children are just forming their view of the world, and they are impressionable. I wouldn’t show “Braveheart” to a five year old, but that doesn’t mean it’s wrong for me to watch it.
The world is messy, and there’s nothing wrong with art reflecting that. Do children need to be exposed to that messiness before they are ready? No. But it’s certainly not a sin for an adult to decide they want to watch something that children in general shouldn’t.