Pajamas Media has a report on political censorship at Wikipedia. Be alert.
Look, I love Wikipedia, because I have become addicted to finding out what the capital of The Gambia is, or what year Gilligan's Island started, all at a moment's notice. Though I suppose with a search engine, Wikipedia isn't so necessary after all. But I don't trust them on anything political or controversial. Its editors have not yet embraced the moral ideal of neutrality and objectivity.
If you have a strong bias about a topic, then you bend over backwards to give the other guy a fair shake. That's a very elementary morality. Which I am not capable of, BTW - I know my editing would favor one side no matter how hard I tried. But that is one reason I don't set myself up as an objective editor of controversial material. I could do pretty well, by sheer effort. But pretty well isn't good enough.
Of course, having a strong bias about a topic usually decreases your ability to see that. You just think you and your friends are right, and the other side populated by jerks and liars. The deeper the bias, the less one perceives it.