I'm not sure this is the right forum for this kind of discussion, but the lockdown means I have tons of free time right now, so...
Except we don't.
Nearly all media that is made for the 'good feels', that has violence, isn't using the violence ITSELF for it. It is depicting the protagonist's agency. It is showing a character that the audience is identifying with using 'power' against the 'enemy'.
This is ONE way of using violence in art. There are others. I don't deny the validity of what you're saying, I just think you're excluding many things that do interest us and that are an important part of art in general.
MOST people are repulsed by violence for violence sake. Sometimes this revulsion is due to us imagining ourselves being the victim of said acts. This often leads to thinking about our own mortality. Or imagining a permanent maiming injury.
But sometimes the thought of committing the violence is just as horrifying. Empathy is a bitch.
MOST people where I come from even think sex should only happen after marriage. And also think science fiction, one of my favorite genres, is a total waste of time. So--what's your point? The tastes of MOST people do not define the limits of art, or even of human taste in all its facets. And, as I say below, MOST people still pay good money to see horror movies with graphic violence. The real question here is, why?
Violence for the sake of violence is used (almost) exclusively in the genre of horror. Because most people are revolted by it.
But you've just named a big problem with your argument. Why is there a whole genre ("horror") dedicated to the violence you claim most people are revolted by? Considering how much money all the violent horror movies make, can you really say there is no interest in violence for violence's sake in fiction? (I think it would be more interesting to ask why there is such an interest than simply trying to deny that it even exists.)
Second. Rape is about power not violence. Violence CAN be that application of power. But it does not need to be.
But violence IS prototypically the application of power (rape is, after all, a form of violence), because it -- prototypically -- has to go against the consent of the violated party, or else there is no violation, no violence. (Or do you consider, say, helping someone commit suicide also violence?)
Third. BDSM is about trust. If you just see someone whipping someone else who is tied up, you are TOTALLY missing the mark.
Yes, but, especially in the B and D parts, violence is its language. You really need the language of chains and whips to make it work. It has to be pretend violence for today's sane-safe-consensual paradigm to apply, but the aesthetics of violence has to be there, or else you go back to vanilla.
If you enjoy violence, or are aroused by it, that's fine. I'm not going to kink shame anyone as long as they are being safe IRL. You do you.
But don't make the mistake of thinking that most people also like it. Because the overwhelming majority does not.
That is true. A kink, after all -- by definition! -- is not a mainstream interest. Yet... considering the success of violence on screen (see "Seven," "Saw," etc.) or in book format, I think you need some nuance there. The US seems fascinated by serial killers (there's even a deck of cards with them, and shows that humanize them like Dexter). Most people may be revolted by violence, or so they say, but a surprisingly high number of them pays good money to see it or read descriptions of it.