It's known that watching violent movies can desensitize people to violence. Racist videos can promote false stereotypes and make them acceptable to young and weak people who don't have strong foundations. Not saying it's true for everyone, but for some it can certainly reinforce racist views just as they can reinforce violence. Adam Lanza, who was either autistic or had Asperger's Syndrome, was said to have developed his aim by watching violent videos. Read "On Killing" by Col. Dave Grossman.