Though I have in fact been allowed to cite Wikipedia by more than one college professor. I usually approach the ones who disallow it to find out their reasons and after dismantling their arguments with "pro-Wikipedia propaganda" all I can see is some inexplicable deep-seated hatred. Why I don't know.
Wikipedia isn't a good source for university level work. Either the article you're using doesn't have references, in which case it's completely unreliable, or it does have references, in which case you should use them instead (there aren't many sources used as references in Wikipedia articles which aren't accessible to university students).
Oh, and the admin bit can be quite useful outside of Wikipedia. [snip]
I know - I've used it like that before as well! Never in an argument with a lecturer, but in less formal arguments with various people.