I get that too in my school, except in this case I'm not allowed to use Wikipedia because the teachers think that if we use it then we just copy and paste the information into our documents / books. It's more so with Global Perspectives, especially where I'm supposed to credit the source. 90% of the time I can assure you that the source is Wikipedia.
I've been more trusting of government websites now, at least they have accurate information 90% of the time and have more credibility than Wikipedia.
It's not called "a free encyclopedia" for no reason.