Do video games or movies promote violence

Yes, they can, but it really depends on the person watching them and their own mental vulnerabilities. If someone is incapable of separating actual violence in their minds from the violence they see and interact with in games and movies, it can potentially cause problems for them. For instance, some who may spend hours playing a game where they shoot and kill others, might roll their eyes and consider it nothing to see a real person's shooting death on the news and may be far too desensitized to care anymore. This could lead to problems in their future if they are prone to violence themselves. This doesn't mean every person who watches violent movies or plays violent games will become violent. It just means that some who are more vulnerable, could be influenced greatly by them. Either to commit violence themselves, or to be apathetic (uncaring of real people being harmed), which can be just as dangerous.