Yes and any reader citing it would be best advised to check the page history and comments section. Teaching that to children would also be a good way of showing and exposing these vandalisms. They might learn to use it better then.

Outright discarding one of the best sources of information humanity has ever created is IMHO just plain wrong. I would understand it if this were people writing doctorates but anything below university level should definitely use it.

It's always good to tech people to check the history and comments. However, when you cite a Wikipedia article, you're supposed to cite a particular revision. That's what the "Cite" link does.

And encyclopedias can easily not have your subject, be based on wrong information, and so on.

Teachers treated them like fact until high school, though: Only in my senior year (1995-1996) were we told that while we could get basic information from an encyclopedia - to help us search for information - we couldn't use the encyclopedia itself as a source of information.

I don't understand why folks aren't treating wikipedia the same way. In general, a wikipedia article is going to give a fairly good faith overview of a subject. There are going to be more subjects than could fit in an encyclopedia. Many articles will be more in-depth and a good number have references: In other words, you can go off and read the source material if you want and use that for more information.