When a person does something they are ashamed of they try to psychologically cleanse themselves? Yes, we know this. Unless you are a sociopath, you've experienced shame in your life and that shame probably led you to do strange things to feel better or alleviate the shame.
Eventually, given enough time you stop being ashamed. Sometimes people accept a normal disposition to whatever act previously caused them shame, others go all crazy and dive right in.
Shame is a natural reaction to perceived wrong or foolish behavior. Once a person no longer perceives an act as wrong or foolish, they stop having feeling of shame about that subject.
Once you have overcome the shame of an act, it is your MORAL behavior that dictates the type of person you are. Take sex for instance, since that seems to be the topic of the month here on the escapist. Some people feel shame when they have or think about sex. Once they overcome that shame and realize it's no big deal, they go on with a normal life and sex is just a part of it. If you are bat shit crazy you might start actively seeking out sex anywhere you can find it or in extremely rare cases go all Floyd Hansen (+1 geek level if you get the reference).
I'm curious to see how exactly not being ashamed of consuming violent media is a bad thing. Some of my favorite things are probably some of the most violent media out there. I watch Spartacus, Breaking Bad & Sons of Anarchy and play some of the most arguably violent and inappropriate videos games on the market and yet somehow I've managed not only to not get any tattoos, but I also haven't raped, maimed or killed anyone yet either. In fact, the thought of hateful violence like racism, rape and nationalism really turn my stomach and I wish we could find a way to shed them.
Perhaps there is a link to shame and violence that maybe if we can conquer shame, we can conquer violence? I mean after all, haven't some of the worst crimes in the history of Humanity come from a violent reaction to shame and embarrassment?