Wikitravel makes every attempt to be fair in articles.
Being "fair" does not necessarily mean being "nice". We have a mission to make (among other things) a reliable and complete travel guide, and a travel guide that doesn't give qualitative information about the things it describes isn't reliable or complete.
We need to call a spade a spade; if a restaurant is crowded, loud, and overpriced, we need to say so. If a hotel has bugs, smells like urine, or is dangerously badly built, we need to say so. If a tourism site is ugly, annoying, or not worth the effort, we need to say so.
If another Wikitraveller disagrees, the description should be edited until both sides agree that the description is fair. If a restaurant's pizzas are tasty and served fast one day, and half-raw despite a one-hour wait the next, then a fair description might say that "service can be slow and quality suffers during rush hour".
However, being "fair" doesn't mean using bland, vapid, or timid prose. Wikitravellers should feel free – nay, obligated – to use concrete, lively descriptions that paint a clear, concise picture of the subject in question. "Greek restaurant just off the plaza" doesn't tell anyone anything. "Dingy but passable Greek restaurant with surly waitstaff, rich and generous portions of moussaka, tinny stereo system" gives a lot more info. You don't have to tone down your writing in Wikitravel just to remain fair.
The idea of "being fair" is this: We don't have any agenda on Wikitravel. We are not advocating any religion, political philosophy, environmental practice, feminist theory, international language, home cooking device, tour company, or any other idea, business, or cause. We aren't trying to put any hotel out of business or punish any restaurant because they wouldn't honor our expired Diners' Club card. We are trying to put personal feelings about destinations behind us, while sharing our knowledge and impressions with other Wikitravellers.
Our agenda on Wikitravel is to achieve our goal: to make a really, really, really good travel guide that's useful and readable for travellers worldwide. We want to share our knowledge, and have it used. We put the needs of the traveller first. With this goal in mind, it's clear that leaving extraneous non-travel ideologies behind is in our best interest. We want to make a travel guide, not a religious tract that scares readers away before they get through the first sentence.
 Neutral point of view
 Local or business owner bias
Remember that as a business owner or a local advocate there may be a temptation to whitewash or sanitize an article or listing and to present a city or a business in the best possible light. There is nothing wrong with wanting to show off the highlights of a city. However, if there is a conflict between the perspective of travellers and the perspective of a business owner or local advocate the traveller comes first.
 Political disputes
Alas, when politics get involved, it's difficult to stay "fair" to both sides at once. The best way out is to stick to the bare minimum of facts necessary, presented as neutrally as possible, while keeping a firm focus on the traveller's interests. For example, a visitor to the West Bank would need to know that the area has been under Israeli occupation since 1967 (a fact) and that it's mostly under the control of the Palestinian Authority (a fact). However, as Wikitravel is not an encyclopedia, we do not need to devote pages and pages to what terms were used by which UN Security Council resolution, what the current positions are on settlements and refugees, and above all whose fault the whole damn mess is. (Substitute the conflict of your choice.) Whoever actually controls a territory, we simply acknowledge the fact that they do control it, regardless of whether we might think they should.