Agreed, and when bias plays such a large part in motivation, as well as content, the result is likely to be skewed anyway. One thing I've learned as a journalist is to argue against my own points thoroughly either before I write, or in the text. ("Balance" by other means...) It's the only way to get hard facts, and to avoid having your own position distort the information content. I write "Opinions" on that basis.
I think we've seen more than enough of the "planned parties" on threads, regarding fearless agreement with each other, to know the value of that material, but lynch mobs start like that, too. An uninformed person could be forgiven for thinking they were looking at some sort of popular uprising, not just selective rantings.
Actual article selection is another problem. I actually can't use a lot of the materials I see, because of content quality and advanced illiteracy and self contradictions, so I have to research the original sources myself. I think for citizen journalism, as a working proposition, editing has to start between the ears.