A systemic bias is the shared beliefs of those who participate. For instance, in a project run and used mostly by Americans, there will be a systemic bias towards w:American Exceptionalism and w:scientism. In a project run and used mostly by Internet users (like any large public wiki) there will be a systemic bias towards technological solutions as being "good".
Edward Wenk Jr. for instance claims that the Bush Administration "lacks tolerance for healthy dissent. The most influential advisers have the same biases as the president, nurturing error, blunder and folly." 
This is different from a systematic bias which arises not from who participates, but from how they work together. Such a bias would be for example voting "machines... highly vulnerable to fraud... concentration of media... the imperative to raise funds for TV ads" and the fact that "the military-industrial-congressional complex controls half the national budget and subverts priorities preferred by the electorate." Obviously these are quite closely related to the systemic bias, but, in theory, they can be differentiated. If we did not believe that, then, we could not believe that a democracy could function while still leaving such obvious power groups in place.
Likewise, we would not believe in "neutral points of view" or "assume good will" unless we thought we could overcome our innate biases to work together. Trying to codify the so-called community point of view is an attempt to at least define the systemic bias of those who participate. It is almost always resisted by those who gain power via this bias alone, e.g. the Wikipedia Liars Club. If you look for m:community point of view, you will not find it, as the liars are engaged in deleting it, to make sure no one realizes they ARE in fact pushing a point of view - which would require in the neutral point of view ideal that it be neutralized by engagement with some opposition, e.g. "trolls".