Does the media dictate what the public sees/hears/reads?
Or does the public dictate what the media shows/says/prints?
I don't think you'll ever find an absolute answer. Do certain media outlets have an agenda? Probably.
However, if you go to a barber-shop, everybody is gonna talk about the prison abuse, thumbs-up, etc. Talking about the surgery in Houston doesn't have the same appeal.
To a certain extent, humans are attracted to sex and violence. Can't blame the media for giving us what we want.