It states Darth Bane is more knowledgeable than any Sith before him.
At the time, he only had the knowledge of the Sith Academy and the holocron of Darth Revan.
And then obviously note the knowledge contained within the academy was nothing to Revan's holocron.
So if basically Revan's holocron alone can make Darth Bane more knowledgeable than Vitiate, Revan would be too.
Simple logic.
... what?
Unsurprisingly, you completely missed the point.
The only two sources of Sith knowledge Darth Bane has at this point is the Sith Academy's and Darth Revan's Sith Holocron.
The Sith Academy's knowledge is grossly inferior to that of Darth Revan's Sith Holocron as well.
If these two sources of knowledge alone places Darth Bane above Vitiate, then clearly Revan's own knowledge must be too.
And that would especially be the case in his prime. It's not that hard to follow the logic here.
However, given that Darth Bane admits he can hardly wrap his head around some of Darth Revan's knowledge, he clearly knows less than Darth Revan.
Therefore, it makes me question the validity of the statement. I did some research and believe the quote was merely summarizing the previous page.
Clearly the similarity between the two quotes is obvious, but this one makes note of it just referring to the Sith Academy.
Otherwise, the quote would directly contradict both primary source material and logic (since Darth Revan does not know more than Vitiate).
To summarize what Ant is saying bit more concisely, Bane as of PoD (the time period that the passage is referring to) couldn't possibly be the most knowledgeable Sith in history when his primary source of knowledge was Revan's holocron. Given that the holocron didn't account for the knowledge Revan had gained afterward, or for other Sith who had more access to knowledge than he, it's much more probable that the quote is in reference to the Brotherhood of the Sith specifically. Especially considering the word choice of the previous paragraphs, which Ant provided above.