Bern, you are steering the argument so far away from PC that it is almost a totally different topic. Hitler, the slave trade, etc etc etc is NOTHING to do with PC. Political correctness is a part - a single tiny slice - of the whole social engineering mechanism. The two are not the same things. It does not depend on your view. You cannot argue that "red is blue depending on your point of view". Red is red. It's an established fact. Likewise PC is an established fact of life (unfortunately), not open to interpretation. What you are trying to express is that any political body will follow what it believes to be "correct" such as Hitler killing Jews or whatever. This is NOT "political correctness".
Political correctness is a single-minded mechanism for guiding public opinion to a specific goal in support of a diverse society. You cannot tamper with its definition. It is what it is.
I find it amazing that Wikipedia is being projected as an unreliable source. Are the dictionaries also wrong? What about answers.com, thefreedictionary.com, phrases.org.uk, deceptikons.com, dictionary.com, politicallyincorrect.me.uk, askoxford.com (a highly academic resource of the Oxford dictionary), ourcivilisation.com (describes PC as "the communal tyranny that erupted in the 1980s"), and many others I could list. They all define PC as the exact same thing. Claiming that Wikipedia has got it wrong is, frankly, clutching at straws in order to continue to live in denial of this horrific political concept.
Any political party that does what it believes to be correct is NOT "political correctness". Telling people to share a certain view or shut up is what "political correctness" is.
Anyone interested in learning more about the utter garbage that is political correctness can read some interesting stuff here:
http://www.politicallyincorrect.me.uk
http://www.capc.co.uk
http://pcwatch.blogspot.com
http://www.ourcivilisation.com/pc.htm
...and for the rest of you who love PC, here's some arguments FOR it (just so I can't be accused of being unbalanced):
http://www.guardian.co.uk/commentisfree/2009/dec/21/philip-davies-political-correctness
http://www.telegraph.co.uk/news/newstopics/religion/4593918/Christianity-in-decline-because-of-political-correctness.html
http://www.students.org.au/political/correctness