This is not a bad summary, at least in regards to the document in question, but not necessarily the part about evaluating primary sources:

According to a claim circulating online, there is a CIA document or internal communication from the 1950s asserting that Joseph Stalin was not a dictator. The existence of this document is cited as proof either that Stalin was not a dictator after all, or at least that even the CIA didn't think he was. However, looking at the document in question, we see it is not a pronouncement of fact by the CIA whatsoever, but an anecdotal information report submitted to CIA information gatherers. As such, the document is a primary source representing the perspective of one anonymous informant, not the opinion of the CIA as a whole. Additionally, the document is contradicted by dozens of more reliable or detailed documents obtained or created by the CIA in the same period, indicating that they did not believe Stalin was non-dictatorial as claimed.