http://en.wikipedia.org/wiki/Querulous_paranoia
Oh sweet irony NA, from your quote:
The terms had until recently largely disappeared from the psychiatric literature, largely because they fell out of fashion after being misused to stigmatise the behavior of people seeking the restitution of valid grievances
Really? You latched onto that one line?
In English, what that means is something like "shyster attorneys, with the help of mercenary practitioners, over-played the crazy-card, ruining a perfectly useful/meaningful dx, when properly/skillfully applied". I am surprised that you, of all people, would be blind to the correct parsing of it.
Analogically, it's like in the 1950's if someone dismissed the complaint of a woman because she's "hysterical". She may very well be irrational/emotional, as a result of her momentary physical condition - much as anyone else can be, for a constellation of reasons - but that particular word, when it fell into common (vulgar) parlance, had to be abandoned, since non-practitioners had adopted the term, and weakened its meaning through misuse and abuse.
"Retarded", for instance, used to be a clinical term of art. In physics or chemistry, a retarded process is (still) one which is slower (relatively) than others. But since every school child (and some bigger children) now use a (former) term of art as an insult to be hurled at a moment's notice, the language of psychology changes.
The language you quote has a footnote linked to if (if you care to learn, rather than argue) which goes into some detail about how authorities (think kangaroo courts) would often make themselves complicit in miscarriages of justice by holding "competency hearings" for the "unpopular".
But I digress...
-t