There are a lot of choices a writer must make-- well anybody putting together a creative project. How much do you reveal of what is there? Where do you sugarcoat something to make the reader comfortable? When do you lose authenticity if you do that? Profanity is one of those issues.
Mostly in my stories, I stick to minor cursing for my lead characters. Once in awhile I put in a -- he cursed graphically or used words she'd never heard that way. But in general I feel it's not necessary to put in the cruder curses. On the other hand, it is definitely ignoring how a lot of people do talk routinely.
Although I rarely curse myself, it's not because I don't know the words. I grew up with a father who had quite a vocabulary. He stopped that language when my babies were born. I am not sure when my husband's father had quit but he evidently also had a pretty wide ranging vocabulary which at a certain point he stopped as I don't remember ever hearing him curse.
Years ago we lived next door to a very nice couple, both doctors, and that lady had come from Brooklyn (which might or might not relate). The swear words she could use and did were unbelievable, and they spewed out no matter who was around as part of her routine conversation. I kind of cringed a bit as I had small children then, but they already were learning words in school that I didn't learn until I was in college.
It was around 1962 when my family was spending an overnight with an aunt where I would be sharing her bed. I had had a date that night; and when I got home, she and I talked awhile lying in bed. I asked her the meaning of a word I'd heard for the first time. Fortunately she knew it.
I had to explain the meaning of the same word to my daughter when she was in the second grade which was likely around 1973. The world had changed a lot in not many years. I lay some of that to videos where movies came into people's homes with language that at one time would have been censored before it hit the small screen.
Personally I am not offended by swear words from others with only a very few exceptions. There are many that used to seem totally unacceptable in polite society but now are heard frequently and from the mouths of very nice people. Some really do express certain situations better than any other words.
Where I don't like to hear them is when someone is angry. It offends me more than I can say if I am having an argument with someone-- which pretty well means my husband as he's about the only one I argue with-- and he uses a coarse phrase. Even more than that I would leave an area immediately if I heard someone using profanity when they were in a rage. Perhaps it goes back to my own childhood because it scares me.
Swearing as part of a routine conversation-- no problem.
Swearing when infuriated-- I'm outta there.
So that's life and how I handle it. In the books though it's often something I have to consider. It's not even just crude words but also those that the religious take offense at hearing. It's nigh unto impossible to write a man's conversation without some of that unless he is a religious person.
So when writing dialogue, I always ask-- should I write it as they would say it-- or as the reader would rather read them saying it? It's a question I ask with each book. Now some characters will never swear as it's not part of their persona. Some wouldn't use a truly crude word. Others though, they do and it's part of who they are. To write their dialogue without it simply gives up part of what makes them who they are (the assumption being that means uneducated or quick to take offense-- but my very educated and not quick to anger neighbor proves that's not always the case).
One absolute for me-- more accurate or not-- I will not use a word that demeans another race or class of people even though I grew up hearing those words too. I just feel they should be forgotten-- not that they will be.
This issue has me thinking about it again as I am editing a story of the rodeo set in 1974 which I plan to put out as an eBook in June. When I originally wrote the story, I sugarcoated the language. Now though it seems as though I'd be leaving out an important part of the atmosphere and energy to do that. By its very nature, this should be a grittier story than some of my others. Earthy language seems not only appropriate but part of the books' truth. The language when a group of men are talking together should be what it would be. Language also differentiates these characters from those who are gross and those who are of a more gentle nature.