Mathematics on Wikipedia is top notch (my training was in mathematics so I can say this with a high level of certainty), but mathematics is hardly controversial. Not surprisingly, the more controversial the topic, the more biased Wikipedia gets. Try to look up any controversial political topic, current or historical, in most cases the objectivity and comprehensiveness of articles are highly questionable.

Also, you would hardly ever see edit wars on math topics, but they happen all the time on politics.