As a general rule, there really is no excuse in polite company for using any of these words, as there are perfectly adequate polite substitutes. Poor manners are just plain poor manners, regardless of whether these words fall into an arbitrary classification. Further, avoiding words in poor taste will force you to be more eloquent if the situation requires strong language. To me, the challenge is, if the situation warrants, to express myself colorfully without using objectionable language.
There is an anecdote attributed to Lyndon and Ladybird Johnson that they were taking a tour of botanical gardens with press coverage. LBJ, notorious for his rough Texan language and abrasive manners, commented to the press that the staff of the gardens must use "really good manure" to raise these beautiful plants. After the President moved on, some reporters asked Ladybird Johnson why she didn't persuade him to use a more polite term like "fertilizer." Ladybird responded that they had no idea how many years it took her to get LBJ to use the word "manure."