Just because the taboo changed does not mean that the Puritan-inside(tm) hardware most Americans have is not there (self-evident on conservatives and very rabid omg-living-in-denial in liberals)
The main point is, in Puritanism, thinking the wrong thing is a sin, so even writing it down is seen as bad. Other cultures can discuss without dirtying their souls/minds/egos.
The issue isn't that "writing it down is bad" its that certain descriptions of a character are going to cause readers to judge that character differently depending on the culture the reader is used to. People who think smoking around children is a bad thing, are going to judge a parent doing that around their children. So, an editor might believe that removing that reference will avoid people focusing on an unimportant detail in a way that negatively affects the story being told.