A lot of teachers seem to be in denial about this.
University instructors' usual directive to students concerning Wikipedia is, "Don't use it." Not very much explanation, just a command. But I know that for me personally, when I need to find out about a few facts, what do I do? I type stuff into a search engine that will probably lead me to... Wikipedia. I do not think I am alone or unusual in this regard.
The difference between instructors and students is that the instructors don't stop at Wikipedia.
Rather than simple prohibition of using Wikipedia (which many students ignore), instructors need to think hard about how we can teach students how to research like a professional. What constitutes good evidence? What can you trust? Why should they used PubMed instead of Google? Or Google Scholar instead of Google's front page? How do you tell if a journal is peer-reviewed? Why is peer review the gold standard?
Instead of giving students direct instruction in these matters, the tendency is to sort of roll it into other classes and hope they pick it up as we go. But why not take the bull by the horns and try to get them to research like professionals do? The current situation is a little like telling them to drive to another city but forgetting to tell them how to use the car.
I don't think many university instructors have really come to terms with the existence of search engines and online information. And perhaps it's not surprising, because most classes have a hard enough time simply getting students past new terms and their definitions. Dealing with strategies for gaining new knowledge, and then evaluating that knowledge, is much more general and subtle.