"Chronically advantaged citizen" is not an urban legend it is a not to read seriously exaggeration to make a point.
Whereas the poster of an urban legend believes it to have a factual basis expressions like 'vertically challenged' or whatever are not posted as factual examples but as exaggerations or irony. If you have the suspicion that some of the examples you have read are urban legends, McGrath, you may have taken serious the jokes page.

Those of you opposing a critique of political correctness by saying that it is simply advisable to try not to be rude misunderstand and underestimate what in my eyes what has led to that critique: The quickening pace with which ever more expressions have been added to the list of better-not-to-use expressions. What had started with good intentions has developed sometimes into a subculture of the easily insulted. That some of the people involved in that project don't like the critique is easily understandable.

That movement was based on a wrong conception stemming from research of Benjamin Whorf. Whorf had claimed to have found that language describing a person/country/thing/subgroup largely determines how we perceive and think about these things/persons. The opposite idea, namely that our perception of and thinking about things/persons determines how we perceive the words used to describe them is somewhat closer to the truth.

The idea that we have to take the words with the bad connotations away in order to facilitate a more neutral thinking about persons described with these words has led in Germany within the last century to altogether three changes in the verbal label given to the concept of 'Social Welfare'. The idea was each time to take the stigma away with which the people being on welfare have been connected. Each time that has failed miserably. The bad connotations have quickly been transferred to the new formerly completely neutral words.

Mind you, I'm all for calling people sharing some attribute with the name they themselves prefer (though sometimes I wish their preferences wouldn't change so quickly; and it is irritating for me that some don't like to be called by a word they themselves used most often among themselves). But this short step (calling them by their preferred name) doesn't change at all underlying prejudices. Within the last decade, the word 'Zigeuner' (Gypsy) has nearly completely been replaced by 'Sinti und Roma' in German. The prejudices stick now on the new (for us, not for them) names. The idea to influence the perceived reality by relabelling has failed once more.

Wolfgang