J. D. Rajotte, cursing, obscenity, etc. are different from other objectionable things in writing in an important way that introduces an ethical consideration. I may write about violent crime, feelings of hatred, wicked acts, etc., but I'm writing about them. But when I write profanity, obscenity, etc., I'm writing them. If I write about an act of cruelty, I don't bring that event into actual existence. If I write obscene language, though, I have brought it into existence. My act creates an instance of obscene language that didn't exist before. It doesn't matter that it's Joe, a character in my story, who says the brutal thing, because the whole story is my saying, my verbal act.
This is not to say that there is no ethical issue also in the description of cruel actions. While a description of a cruel action is not a cruel action, it does invite a reader, through use of the medium of words, to consider to contemplate, such an action in imagination. The odds are great that the reader will not attempt to enact the cruel action, but it may remain alive in his or her imagination, and, myself, I don't see imagination as somehow a compartment in my consciousness in which any amount of "radioactive" substance may be safely stored. But this is a separate matter from the one your initial posting raised. It might help to clarify the uniqueness of the topic you did raise and its relationship to other things that might be wrong in storytelling.