Some people are really affected in adverse ways, inability to sleep and obsessive replay thinking. Primarily happens with sensitive and empathic individuals. People should not be forced to watch brutal videos. I do not expect you to understand.
I watched a video of a Russian soldier being beheaded by a chechen, it was extremely brutal and had a lasting negative effect on me.
I remember in 2001/2002, the Daniel Pearl video had an effect on me and my mother too.