In a lot of fields, words become dirty. This isn't really a post about being able to say the word "cunt" on live TV, but rather words that are politically expedient not to say.
For instance, in certain sects of Christianity, it almost became dirty to call Christianity a religion. It's a "personal relationship with Jesus" or something. This seems to have come about from the very optimistic future of the 1900s to 1950s, where it seemed like science could solve anything, and religion was yesterday's horse.
In politics, this happens regular. Socialist IS communist, at least according to the listeners of deep southern radio. Republican IS fascist, and so on.
This is a fairy standard linguistic shift. Even if one wants to talk about the ideas of Marx reasonably, you couldn't. Not, at least, if you were a member of a major political party. The words, the language, of Marx (say) have(has) become dirty.
This is also a rather standard problem in Psychiatry. Normal psychiatric classifications (for all their softness) become insults by virtue of being associated with mentally affected people. Eventually, Psychiatry as a profession needs to come up with new terms. From idiot, to retarded, to developmentally delayed. The commentary on that fact is endless and repetitive.
But in politics, one of the loudest of professions, these "bad words" can almost entirely define a group, or rather define what they are not. At least when it comes to discourse. Far be it from me to suggest that what comes out of a politicians mouth reflects his or her sincerely held beliefs.
Somewhat cynically, we all engage in politics. We know, in our heart of hearts, who are the more powerful people in our community theatre, or even in a small friend group. They choose where to eat, what to do, and so on. Perhaps we can find out more about ourselves by examining what it is we are not saying to our friends.