I remember all of our encyclopedias being decades out of date growing up. My parents bought a set of Encyclopedia Brittanica in 1976 or something like that, so by the time I was reading the Encyclopedia for research on papers in the late 90s and early 00s, it was without a doubt less factual than even the earliest incarnation of Wikipedia was.

Either way, you are correct, we weren't allowed to cite any encyclopedia, but they were meant to be jumping off points for papers. After Wikipedia launched when I was in 9th grade, we weren't allowed to even look at it (blocked from school computers).

I definitely used it though.