Whilst we may wish to strive for objectivity (and fail repeatedly - http://www.theregister.co.uk/2010/07/16/dab_promotion_fail/), one of the strengths of Wiki is that peer review is built into the system. Anybody can question/correct material that it posted, and while there are plenty of examples of silliness and stupidity (http://www.theregister.co.uk/2010/07/14/blatter_order/), the general order of the day is verifiable source trumps opinion.
“A peculiar and dislikable person” colours the judgement. There are many ways to say that somebody is a non-conformist without leading the readers emotions. Indeed, there are many who fit into society's norms who are likely to prove to be more dislikable people. To that end, it is - as you say - a short and concise definition, but it is also a bad definition.
You are correct that Wikipedia can never be a *trusted* source of information, however for all of the day to day questions, Wiki is just fine. To give an example, if I am bitten by a mosquito and it hurts like hell, I'd like to know why it hurts once the little critter has up and left. http://en.wikipedia.org/wiki/Mosquito#Feeding_habits_of_adults
This is not the same as trusting something written in Wikipedia in a legal or technical sense. There are differing levels of trust depending upon what the information is and how important it is to what you plan to do with said information. To put it another way, I have a copy of the original "A Brief History of Time", some parts of which have since been retracted and other parts revised and refined. Is this one man's heart over his head, or is it simply a consequence of attempting to explain what we don't fully understand and thus revising these explanations in the light of new evidence? Given discussions that take place on these very forums, I wonder what Wiki says about climate change... This all leading to question the objectivity of scientists and experts in print, never mind Wiki articles. Are we looking at the truth? Are we looking at a pet theory the author doesn't want to let go of? Are we looking at manipulated figures chosen to reach a predetermined conclusion (ClimateGate is all about this; as is much of the history of the "smoking [doesn't] kill[s]" tests and examinations). Or are we looking at what is merely a best guess? The entirety of human knowledge is not infallible, in fact it is riddled with myths, hoaxes, and inaccuracies, perhaps the biggest of which is the desire to slave to please an omnipotent master. There isn't so much as a shred of actual solid evidence, yet followers will happily point to their own self-published guidebooks as both evidence and a life manual, some willing to take it to the degree of ostracising (or even harming) those who do not fit into their "norms". Given this sort of thing runs rampant in humanity, it is really no surprise Wiki is what it is. It may strive to be the best of collected knowledge, and it may fail epically at times. At least it offers means to revise, update, question, discuss. This is where it wins over a dictionary. It is more interactive. Sure, slobbering masses may point at an article and say "if it is in Wiki, it must be true", the slightly better of us would consider Wiki to be a ground research tool useful for covering the basics before lauching into more involved research; pretty much like your high school maths teacher would have taught you plane geometry before invalidating much if it when it comes to three dimensional objects...
You ask for primary source material. The first question is how do you know this material is correct, or are you placing more trust in it because it is in print? The second question... sometimes said source material is difficult to find. My mother is a great believer in old-fashioned research, but there was only so much that would fit into Woking library. The Intenet annoys her as looking up specialist articles (i.e. causes/treatments of certain medical issues (for friends, she was a nurse way-back-when)) often brings up websites with totally different, contradictory, opinions. I do wonder, however, if she was in Woking library, if she found her answer in a book, would this suffice, or would she carry on looking in other books to verify the acuracy of the information. The thing is, actually going to a library and actually finding information and actually looking over and over to confirm said information is quite a time consuming task; this coupled with many people *trusting* something that is in a textbook or reference (even if it is wrong or only tells a half-truth). It is much easier to clicky-clicky but doing so has the danger of providing contradictory information. Are some people just plain wrong, or is it a subject about which we don't know as much as we like to believe we do? If the latter, how often does a printed reference book point out its own level of accuracy?
Genesis 1.1... Citation needed... :-)