I think we just crave excitement in life.
The way we are wired, it's inevitable that violence and sex will invoke strong reactions.
We are wired to like sex for the obvious reason of passing on genes, but I don't think we are exactly wired to enjoy violence, except maybe the adrenaline rush those situations might provoke.
I feel our reactions to violence will be dependent on our interpretation of it.
A lot of people are bored with their life of predictable routine, so they'll go to nascar, see people driving insanely fast and possibly crashing.
Back in the days they're miserable lives were atoned for by the slaughters that ensued in the Colosseums.
Your reaction to violence will be deeply dependent on the dominant world view of the society you inhabit. America is a war nation, the idea that you guys love violence will be promoted.
Go to a Buddhist nation and you'll find out we aren't predisposed to seek violence.