My problem with this thread is not the act, which is not my cup of tea, not the fact that people have different opinions, which is only logical and IMHO a good thing, but the judging of other people.
A few hundred years ago, anal sex was viewed in much the same way this is viewed right now. The anus is not the cleanest of areas, not meant for a penis & can cause physical harm, which back then could lead to infections since people generally didn't lead such a hygienic life as people do today (buttplugs and other tools which many pornstars use today to stretch their asshole before a scene didn't exist back then). Also, since a lot of children died before they learned how to walk & speak, it was considered a waste of perfectly good seed.
People who had anal sex were seen as gay or insane (back then it was the same thing).
Today, watching people kill eachother & enjoying it (not necessarily sexually) is considered insane, but back in the Roman Empire, it was considered to be a normal way to pass time.
In Japan, sex with minors is allowed (if you ever play a Hentai game & see a girl that's supposed to be 18, be assured that she's not 18 yet in the original Japanese version), but showing sexual organs in media isn't. To most Western people, this is insane, yet Japanese people consider it to be perfectly normal.
Back in the early 20th century, there were still tribes in Papua New Guinnea that ate their beaten enemies. Totally insane to us, but to those people perfectly normal.
Owning guns is perfectly normal in the US and even though the person using the gun is a criminal, a gun itself only has one use, shooting living beings & will thus only be used by criminals. To most people outside of the US this right is insane, yet, in the US a large majority agrees that it's perfectly sane.
I could go on for a while about the following subjects: Soft Drugs (the Netherlands), Abortion (Ireland & the US), Euthanasia (more & more European countries), etc...
Independent psychiatrists and independent psychologists have been arguing what is sane & what isn't for years and they still haven't reached a conclusion (& probably never will).
Since society of the group is slowly but surely making place for a society of the individual (something I don't like, but that's an entirely different discussion) & since it's society that decides what's sane & acceptable & what isn't, this discussion you've been having will lead nowhere. In the end it's the individual that decides what is sane & what isn't.
This thread is about whether it's sane or insane to do or watch such scenes & there simply is no yes or no answer.