Regular news isn't authoritative either
Yeah, Wikipedia isn't authoritative, the accuracy is random, and the editorial process isn't as deep as the New York Times's, but think about the last time you were at a newsworthy event and compared the press reports with what you saw for yourself. If the news-reading public was lucky, the reporter actually had some understanding of the topic (that's often not true about technology or science or war or world politics, but reporters are often perceptive even if they're not knowledgeable.)
A big part of a news editor's job is to make sure the reporting covers stories that are interesting, where interesting is usually defined as "sells newspapers or attracts viewers/listeners". In some news sources, that means making sure that the story is accurate; in some it means making sure that the story matches the correct political slant or artistic preferences. We'll see if including Wikipedia gets Google enough interestingness.
Wikipedia articles are fairly good about accuracy, because they're usually written by people who care about the topic they're writing about and may even know something. Occasionally you get, say, news about elephants and Stephen Colbert, but even that's still somewhere on the accuracy scale between Fox News and the Weekly World News.