I try to be silly rather than explicitly vulgar for my own sanity. Having a comment about a hack that "stinks worse than expired chicken nuggets" or seems to have been "composed by a series of dartboard throws at random character sheets" is way more fun to me.

That said, I don't take issue with cursing in code that remains private to the development staff. As others have said more eloquently than I can, the issue is when it is exposed to customers who might take issue and churn. Not a good look, so for better or worse, there are professions where professionalism cozies up to sterile language.