why don't teachers like us using wikipedia?

Because they are wikiphobic

Teachers want students to find a accurate source, and wikipedia wasn't taken as a legitimate encyclopedia?

When Wikipedia first became mainstream it was deemed to be less than accurate. Teachers recommended that students not use it because it ran the risk of misinforming students; worse than uninformed students.

Maybe because that site can be a joke at times .

Wikipedia can be edited by anyone.

just take a read through Joe Biden's page and look at all the untrustworthy junk on there.

on the other hand, you can ALWAYS still use the reference links at the BOTTOM of each Wikipedia page, as there are numbers next to the sentences that have them.

you still want to check on them, to be sure they are trustworthy sources, and not filled with BIAS and Slander.

The information contained in Wikipedia is not always 100% accurate.

Anyone can log on to Wikipedia and make changes to a document or add their own documents without being Fact Checked.

Maybe you should ask them, instead of generalizing.