Critical thinking requires that the sources themselves are evaluated for bias. Anecdotally, I've come across several articles for which the bulk of citations all come from one source, and that source is a heavily political "newspaper" article. This is true for topics that are hot on all sides of whatever spectrum or division they tend to land. If Wikipedia is going to be taught to be used as a tool for research, then its governance structure should be taught and critically evaluated. The bias of the board of the Wikimedia Foundation should be taken into account.
I suspect that the bulk of readers don't give a second thought to Wikipedia's Magisterium.