I think your point is fair, but there are also some humans (who are not just politically correct ideals) who don't lace their speech or writing with swears, eve

I think your point is fair, but there are also some humans (who are not just politically correct ideals) who don't lace their speech or writing with swears, even under duress or stressful conditions - they're still talking like humans, too. It would be no less raw or authentic if the character was one of these people. To be clear, the character is a foul-mouthed variety of person. But if he weren't, and the book were absent of swearing, it would not seem any less authentic to me.