Controversial pages on Wikipedia (contemporary politics, etc) are typically hard to edit. Others are easy to edit. Vandalism is rare and temporary, and nobody is going fight earnestly over topics such as how a light bulb or an electric engine works, or when a certain building was build or most historical events, etc.

Wikipedia does not absolve you from checking references or the credibility of the text, but it does a damn good job collecting and pre-checking a lot of the content. You still need to be able to recognize hot-button topics and take those with a grain of salt. And as I said usually those pages cannot be edited by everyone.

The school does not seem to understand how Wikipedia works. At all.