No, they do not cause violence. What causes violence is a lack of self-control. Where do kids learn "lack of self-control"? How about a parent that can't keep a lid on their temper?
I found a study that was done back in 2002 that shows a very strong correlation between corporal punishment and school shootings. You can read it <a href="https://pdfs.semanticscholar.org/841c/25799f333a0e834a1ca6de84ddadeebf3aa6.pdf". It's interesting that study didn't really make the news. If it did, well, adults might have to modify their behavior.
Violence is taught, it is not instinctual. Someone who is not raised by violence will probably not want to watch a violent movie, anyway. Someone who was raised with empathy will probably feel a little nausea watching people get creamed in a fight in a movie.
When kids are hit by adults, the adults are teaching kids what it means to not have control over how they act when their emotions are strong. When adults have strong feelings, but can sit down and talk to their kids, kids learn how to soothe themselves and talk about their feelings and thoughts. That's the difference between no control and self-control.
I hope that someday, the human race figures this part out.
You raise some very valid points, thankfully, I was never hit as a child and would never consider hitting mine.
Thank you. I'm glad to learn that you and your kids have been so fortunate. That is to me, priceless.