It ends with the comment that the meaning of these terms varies radically with the set of prejudices. This brings up an interesting case where the speaker and listener have substantially different prejudices about the group. The meaning that the speaker is conveying includes or at least refers to his own prejudice, but the hearer has a potentially different set of prejudices and hears the term accordingly. Additionally, the underlying premise that the speaker subscribes to a derogatory view of the target group is conveyed, even if it isn't exactly clear what the derogatory view is.
Since the prejudice is part of the meaning of the terms, the ambiguity that comes from differing prejudices makes these terms prone to misunderstandings when the speaker incorrectly assumes a shared opinion. This superficial misunderstanding about specifics in no way invalidates the underlying correct understanding that by using a pejorative the speaker is expressing a strong negative opinion about the group.
This distinction becomes clear when contrasting the confusion that comes from the transition when a previously neutral terms becomes pejorative versus the confusion that comes when a bigot speaks to someone who does not share a particular prejudice. As an example of the former, consider some time around the 1970's when the neutral term to refer to people native to Asia and thereabouts plus their descendants was "oriental." Around that time, the word became a pejorative and was eventually replaced with the term "Asian" As an inevitable part of the transition, people from the dialect groups that changed later would talk to those from groups that changed earlier. The speaker, who had possibly never heard the term "Asian" nor knew of any reason for the term "oriental" to cause offense, would use the term to someone for whom the term was a pejorative. In this case, the hearer might incorrectly assume that the speaker was a bigot based on the language usage, even though bigots and non-bigots alike in the speakers dialect group were using the term. Over time as a kind of critical mass formed from similar interactions, the dialects influenced each other and spread the pejorativization of "oriental" from dialect to dialect. After the transition, the assumption that using the term "oriental" implied that the speaker had a dim view of the becomes correct for continued usage (but not retroactively to pre-transition usage). This does allow for some awkward artifacts like the "CP" in "NAACP"
This brings up the much more challenging topic of how neutral the non-pejorative terms are. My initial theory was that language would demand a term that referred to any frequently discussed group such that the term did not have a pejorative standing. Whenever one such term became pejoratized, another would be generated to take its place. When the sentiments surrounding the group were particularly charged, the process of pejorativization and replacement would be accelerated. I had been trying to work up an experiment to distinguish group-reference from group-description in the various terms. To date the results have been inconclusive at best, and seem to suggest that even the most neutral terms must invoke a prototypical image of a group member. In doing so, they are subject to many of the same phenomena that the pejorative counterparts are.
That said, there can be no question that a person using a vulgar term like "zipperhead" is being insulting in a way that a person using a term like "Asian" is not. Some day I hope to write a Part III that explains why and how one term is so much more offensive than the other, but first I'll need to figure that out.