I don't see anything unprofessional there. Just naughty words. But, the naughty words are somewhere where they warn you that the code below doesn't behave as expected, or complain because there isn't a better way to do something. That seems like the best time to use strong language.
Cleaning it up is a great idea in theory, but in practice almost everybody has higher priority things to be doing. Leaving a comment in the code for why something is ugly is the best thing you can do when you don't clean something up, so that someone coming along after you doesn't struggle with it. We have no idea how many "naughty" comments are no longer there because the issues they addressed were cleaned up.